<PAGE>   1
                                                                   EXHIBIT 10.37




                                3333 LEE PARKWAY


                                  OFFICE LEASE


         THIS OFFICE LEASE (this "Lease") is made as of the _____ day of
___________________, 1996, by and between Crescent Real Estate Equities Limited
Partnership, a Delaware limited partnership ("Landlord"), and the Tenant named
below.

                                        WITNESSETH:
<TABLE>
         <S>     <C>                                        <C>
         1.      BASIC PROVISIONS.   
                                     
                 (a)      TENANT:            PageMart Wireless, Inc.                                      
                                             -------------------------------------------------------------
                                             6688 North Central Expressway                                
                                             -------------------------------------------------------------
                                             Suite 800                                                    
                                             -------------------------------------------------------------
                                             Dallas, Texas  75206                                         
                                             -------------------------------------------------------------
                                     
                 (b)      BUILDING:          3333 Lee Parkway                                             
                                             -------------------------------------------------------------
                                             Dallas, Texas  75219                                         
                                             -------------------------------------------------------------
                                                                                                          
                                             -------------------------------------------------------------
                                     
                 (c)      PREMISES:          Suite     , on the       floor of the Building
                                                   ----         -----                      
                                     
                                             Approximate Rentable Area of the Premises(1):
                                              30,000                  square feet(2)
                                             ------------------------        
</TABLE>




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     1   Landlord agrees that Tenant shall have the right to cause the Rentable
Area of the Premises to be verified by an architect selected by Tenant and
approved by Landlord, at Tenant's sole cost and expense, one time only, after
each of the following dates, and with respect to that portion of the Premises
then being added only: (1) the Commencement Date of this Lease (as such term is
defined in Paragraph 3 of this Lease), (2) the First Expansion Space
Commencement Date (as such term is defined in Rider No. 101 attached to this
Lease), and (3) the Second Expansion Space Commencement Date (as such term is
defined in Rider No. 101 attached to this Lease), or one time only, with
respect to the entire Premises, after the Second Expansion Space Commencement
Date.  The results of any such verification shall be binding on both Landlord
and Tenant, and in the event of a discrepancy between the Rentable Area of the
Premises as determined by the architect and the Rentable Area specified in this
Paragraph 1(c), the Lease shall be modified to reflect the actual Rentable Area
of the Premises.

     2   Landlord and Tenant agree that after the Second Expansion Space
Commencement Date (as such term is defined in Rider No. 101 attached to this
Lease), Tenant shall lease a total of approximately 120,000 rentable square
feet in the Building, and that such space shall consist of all of the eighth,
ninth, tenth, eleventh, and twelfth floors, and a portion of the first and
seventh floors of the Building; provided that, at Landlord's option, Landlord
may substitute the fifth floor of the Building for the seventh floor of the
Building.  The Premises shall be constructed by Landlord and occupied by Tenant
pursuant to the terms and conditions of the Construction Agreement and Rider
No. 101 attached to this Lease.  On or before each of the following dates, (i)
the Commencement Date of this Lease, (ii) the First Expansion Space
Commencement Date, and (iii) the Second Expansion Space Commencement Date,
Landlord and Tenant will enter into an amendment to this Lease modifying the
description of the Premises to include the applicable space and containing
other appropriate terms and conditions related to the addition of such space.
<PAGE>   2
<TABLE>
                 <S>      <C>                               <C>
                                                            Rentable Area of the Building:
                                                             233,484             square feet(3)
                                                            ---------------------              

                 (d)      BASIC RENTAL:                     Months 1-12:  $           per month; annual rental rate per
                                                                           ----------                                  
                                                            square foot of Rentable Area:  $17.70.
                                                                                            ----- 

                                                            Months 13-24:  $           per month; annual rental rate per
                                                                            ----------                                  
                                                            square foot of Rentable Area:  $17.95.
                                                                                            ----- 

                                                            Months 25-36:  $           per month; annual rental rate per
                                                                            ----------                                  
                                                            square foot of Rentable Area:  $18.20.
                                                                                            ----- 

                                                            Months 37-48:  $           per month; annual rental rate per
                                                                            ----------                                  
                                                            square foot of Rentable Area:  $18.70.
                                                                                            ----- 

                                                            Months 49-72:  $           per month; annual rental rate per
                                                                            ----------                                  
                                                            square foot of Rentable Area:  $18.95.
                                                                                            ----- 

                                                            Months 73-84:  $           per month; annual rental rate per
                                                                            ----------                                  
                                                            square foot of Rentable Area:  $19.20.
                                                                                            ----- 

                                                            Months 85-96:  $           per month; annual rental rate per
                                                                            ----------                                  
                                                            square foot of Rentable Area:  $19.70.
                                                                                            ----- 
</TABLE>





__________________________________

     3   Landlord agrees that the Rentable Area of the Building specified in
this Paragraph 1(c) shall not be modified during the initial term of this
Lease, except in the event of an expansion or addition to the Building, if any.



                                     -2-
<PAGE>   3
<TABLE>
                 <S>      <C>                      <C>
                                                            Months 97-108:  $           per month; annual rental rate per
                                                                             ----------                                  
                                                            square foot of Rentable Area:  $19.95.
                                                                                            ----- 

                                                            Months 109-128:  $           per month; annual rental rate
                                                                              ----------                              
                                                            per square foot of Rentable Area:  $20.20.
                                                                                                ----- 

                 (e)      SECURITY DEPOSIT:                 $190,900.00                                                 .
                                                             ----------------------------------------------------------- 

                 (f)      LEASE TERM:                       Ten (10) years and eight (8) months                         .
                                                            ------------------------------------------------------------ 

                 (g)      ESTIMATED
                          COMMENCEMENT DATE:                June 1                                                , 1997.
                                                            ------------------------------------------------------       

                 (h)      OPERATING EXPENSE STOP:  The quotient of (i) the amount of the Actual Operating Expenses for
                                                   the Project for the calendar year 1997, divided by (ii) the number of
                                                   square feet of Rentable Area in the Building.

                 (i)      PERMITTED USE:           General office use(4), but excluding(5) any use for collection
                                                   agency, credit processing or telemarketing purposes.
</TABLE>

         2.      LEASE GRANT.  Landlord hereby leases to Tenant and Tenant
hereby leases from Landlord the Premises described above, which will(6) consist
of(7) approximately 30,000 square feet of Rentable Area (herein so called)
located on the _____ floor(s) of the building described above (the "Building"),
as shown in Exhibit A-1.(8)  The Premises are located in the Building which is
located on the real property described in Exhibit A-2 attached hereto





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     4   , including employee training, data processing, customer service,
retail sales and service,

     5   (except  to the extent  that the  following services  are provided
for Tenant's  benefit only,  and not  for the benefit of a third party)

     6   initially

     7   a minimum of

     8   which shall be attached hereto pursuant to Rider No. 101 attached
to this Lease. Landlord shall lease to Tenant and Tenant shall lease from
Landlord additional space in the Building pursuant to the terms and
conditions of Rider No. 101 attached to this Lease.

                                      -3-
<PAGE>   4




(the "Land").  The Land, the Building, the parking facilities, parking garage
and other structures and improvements, landscaping, fixtures, appurtenances and
other common areas now or hereafter placed, constructed or erected thereon
comprise the project (the "Project") known as 3333 Lee Parkway in Dallas,
Dallas County, Texas.  Tenant is hereby granted a nonexclusive right to use the
Common Areas during the term of this Lease for their intended purposes, in
common with others, subject to the terms and conditions of this Lease,
including, without limitation, the rules and regulations promulgated by
Landlord.  "Common Areas" will mean all areas, spaces, facilities, and
equipment (whether or not located within the Building) made available by
Landlord for the common and joint use of Landlord, Tenant and others,
including, but not limited to, tunnels, walkways, sidewalks and driveways
necessary for access to the Building, Building lobbies, landscaped areas,
enclosed mall areas, loading areas, public corridors, public restrooms,
Building stairs and elevators, drinking fountains and such other areas and
facilities, if any, as are designated by Landlord from time to time as Common
Areas.  "Service Areas" will refer to areas, spaces, facilities and equipment
serving the Building (whether or not located within the Building) but to which
Tenant and other occupants of the Building will not have access, including, but
not limited to, mechanical, telephone, electrical and similar rooms, and air
and water refrigeration equipment.  This Lease is granted subject to the terms
hereof, the rights and interests of third parties under existing liens,
easements and encumbrances affecting such property, all zoning regulations,
rules, ordinances, building restrictions and other laws and regulations now in
effect or hereafter adopted by any governmental authority having jurisdiction
over the Project or any part thereof.

         3.      LEASE TERM.  This Lease shall be for the term of years
described above, commencing on the(9) of (a) the Estimated Commencement Date
set forth in Paragraph 1,(10) (b) ten (10) days after Landlord's substantial
completion of the Finish Work, as such term is defined in the Construction
Agreement (as defined in Paragraph 4),(11).  The date the Lease Term commences
shall be referred to in this Lease as the "Commencement Date".  If the Lease
Term expires on a date other than the last day of a calendar month, Landlord
and Tenant shall be deemed to have agreed that the Lease Term shall be extended
through the last day of the calendar month in which the expiration date falls
(the "Expiration Date").  On the Commencement Date(12)  Tenant will, within ten
(10) days after





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     9   later

     10  or

     11  but if Tenant takes  possession of  the Premises for the  conduct of
business before  either such date, then  the Lease Term shall commence on the
date Tenant in fact occupies the Premises

     12  of this Lease, the First Expansion Space Commencement Date, and the
Second Expansion Space Commencement Date,

                                      -4-
<PAGE>   5
request from Landlord, execute, acknowledge, and deliver to Landlord a
statement in the form of Exhibit B attached hereto.(13)

         4.      CONSTRUCTION.  In the event any construction of tenant
improvements is necessary for the Premises, such construction will be
accomplished and the cost of such construction will be paid in accordance with
a separate "Construction Agreement" (herein so called) between Landlord and
Tenant(14).  Except as expressly provided in this Lease or in the Construction
Agreement,  Tenant acknowledges that Landlord has not undertaken to perform any
modification, alteration or improvement to the Premises.

         5.      TENANT'S BASIC RENTAL OBLIGATION.  Beginning on the
Commencement Date, all Basic Rental shall be paid monthly by Tenant to Landlord
in advance on or before the first day of each calendar month during the Lease
Term, without demand, deduction or setoff(15).  All rental and other payments
which are due hereunder shall be made payable to Landlord.  Tenant agrees to
pay said rental and other payments to Landlord at Crescent Real Estate Equities
Limited Partnership, P.O. Box 844255, Dallas, Texas 75284-4255, or at such
other place as may from time to time be designated in writing by Landlord, in
lawful money of the United States of America without any prior demand therefor
and without any deduction or setoff whatsoever(16).  If the day on which Basic
Rental is first due is other than the first day of a calendar month, rent for
such partial month shall be prorated on a daily basis.

         6.      TENANT'S ADDITIONAL RENTAL OBLIGATIONS.

                 (a)      Additional Rental.  Beginning on the Commencement
         Date, Tenant shall pay to Landlord each calendar year the Additional
         Rental (herein so called) equal to Tenant's proportionate share of (i)
         the Actual Operating Expenses (defined below) for the Project for such
         calendar year in excess of (ii) the Operating Expense Stop multiplied
         by the number of square feet of Rentable Area in the Building.
         Additional Rental shall be prorated on a daily basis for each partial
         calendar year in the Lease Term.  Tenant's proportionate share shall
         be based on the ratio which the Rentable Area in the Premises
         (adjusted for office expansions) bears to the Rentable Area within the
         Building(17).





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     13  Tenant shall  have the option  to terminate  this Lease pursuant  to
the  terms and conditions  of Rider  No. 501 attached to this Lease.

     14  attached hereto as Exhibit C and incorporated herein for all purposes

     15  , except as otherwise set forth herein

     16  , except as otherwise set forth herein

     17  (adjusted for Building expansions)

                                      -5-
<PAGE>   6
         Rentable Area of the Premises and Rentable Area of the Building shall
         be computed in accordance with Paragraph 19(x).

                 (b)      Adjustment of Actual Operating Expenses.
         Notwithstanding any language herein to the contrary, if the Building
         is not fully occupied during any calendar year of the Lease Term,18)
         Actual Operating Expenses(19) shall be determined as if the Building
         had been fully occupied during such year.  For the purposes of this
         Lease, "fully occupied" shall mean(20) occupancy of(21) of the
         Rentable Area in the Building(22).

                 (c)      Actual Operating Expenses Enumerated.  Actual
         Operating Expenses shall include all expenses, costs and disbursements
         of every kind and nature incurred or paid by Landlord in connection
         with the ownership and/or the operation, maintenance, repair and
         security of the Project, including, without limitation, expenses for
         the following:

                          (i)     garbage and waste disposal;

                          (ii)    janitorial service and window cleaning for
         the Building and the Common Areas and Service Areas (including
         materials, supplies, Building Standard light(23) and ballasts,
         equipment and tools therefor and rental and depreciation costs related
         to any of the foregoing) or contracts with third parties to provide
         same (the term "Building Standard" as used herein shall mean the type,
         brand and/or quality of materials Landlord designates from time to
         time to be the minimum quality to be used in the Building or the
         exclusive type, grade or quality of material to be used in the
         Building);

                          (iii)   security;

                          (iv)    insurance premiums (including, without
         limitation, property, liability and any other types of insurance
         carried by Landlord with respect to the Building and the Common Areas
         and Service Areas, the costs of which may include an allocation of a
         portion of the premium of a blanket insurance policy maintained by
         Landlord);





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     18  those

     19  which vary with occupancy

     20  the actual occupancy of the Building or

     21  ninety percent (90%)

     22  , whichever is greater

     23  tubes

                                      -6-
<PAGE>   7
                          (v)     real estate taxes, assessments, business
         taxes, excises, and any other governmental levies and charges of every
         kind and nature whatsoever, general and special, extraordinary and
         ordinary, foreseen and unforeseen, which may during the Lease Term be
         levied or assessed against, or arising in connection with the
         ownership, use, occupancy, operation or possession of, the Building
         and the Common Areas and Service Areas, or any part thereof, or
         substituted, in whole or in part, for a real estate tax, assessment,
         excise or governmental charge or levy previously in existence, by any
         authority having the direct or indirect power to tax, including
         interest on installment payments and all costs and fees (including
         attorneys' fees) incurred by Landlord in contesting or negotiating
         with taxing authorities as to same, but excluding any inheritance,
         estate, succession, transfer, gift, franchise, corporation, income or
         profits tax imposed upon Landlord;

                          (vi)    water and sewer charges and any add-ons;

                          (vii)   operation, maintenance, and repair (to
         include replacement of components(24)) of the Building, including but
         not limited to all floor, wall and window coverings and personal
         property in the Common Areas, Building systems (such as heat,
         ventilation and air conditioning systems), elevators, escalators, and
         all other mechanical or electrical systems serving the Building and
         the Common Areas and Service Areas and service agreements for all such
         systems and equipment;

                          (viii)

                          (ix)    license, permit and inspection fees;

                          (x)     compliance with any fire safety or other
         governmental rules, regulations, laws, statutes, ordinances or
         requirements imposed by any governmental authority or insurance
         company with respect to the Building during the Lease Term;

                          (xi)    wages, salaries, employee benefits and taxes
         (or an allocation of the foregoing) for personnel(25) working full or
         part time in connection with the





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     24  ; provided, that if such components are properly classified as capital
in nature, the cost of such components shall be included in Actual Operating
Expenses and amortized pursuant to subparagraph (xv) below only to the extent
that the replacement of such components constitutes a Required Capital
Improvement or Cost Savings Improvement, as those terms are defined in such
subparagraph

     25  , at or below the level of regional property manager and regional
asset manager,

                                      -7-
<PAGE>   8
         operation, maintenance and management of the Building and the Common
Areas and Service Areas;

                          (xii)   accounting and legal services (but
         excluding(26) legal services in connection with negotiations and
         disputes with specific tenants unless the matter involved affects all
         tenants of the Building);

                          (xiii)   management fees for the Building(27) and
         Landlord's overhead expenses directly attributable to the Building,
         including without limitation, the cost of an office in the Building
         maintained for management of the Project;

                          (xiv)   indoor and outdoor landscaping;

                          (xv)    depreciation (or amortization) of Required
         Capital Improvements and Cost Savings Improvements.  "Required Capital
         Improvements" will mean capital improvements or replacements made in
         or to the Building in order to conform to any Applicable Law.(28)
         "Cost Savings Improvements" will mean any capital improvements or
         replacements which are intended to reduce, stabilize or limit
         increases in Actual Operating Expenses.  The cost of Cost Savings
         Improvements will be amortized by spreading such costs uniformly over
         a term equal to the lesser of (a) the period of years over which the
         amount by which Actual Operating Expenses are reduced would be equal
         to the cost of such installation or (b) ten (10) years.  The cost of
         Required Capital Improvements and depreciable (or amortizable)
         maintenance and repair items (e.g., painting of Common Areas,
         replacement of carpet in elevator lobbies), will be amortized by
         spreading such costs uniformly over a term equal to the lesser of (A)
         the period employed by Landlord for federal income tax purposes or (B)
         ten (10) years;

                          (xvi)   ; and





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     26  accounting and

     27  (which fees shall not exceed five percent (5%) of the gross revenues
for the Project)                    

     28  For purposes of this Paragraph 6(c)(xv), Landlord represents that, to
Landlord's current and actual knowledge, the Building is in compliance with all
Applicable Laws in effect as of the execution of this Lease.  This
representation shall not apply to The Americans With Disabilities Act and the
Texas Architectural Barriers Act, and all rules, regulations and guidelines
promulgated thereunder.

                                      -8-
<PAGE>   9
                          (xvii)  expenses and fees (including attorneys' fees)
         incurred contesting the validity or applicability of any governmental
         enactments which may affect Actual Operating Expenses.

                 (d)      Exclusions from Actual Operating Expenses.  Actual
         Operating Expenses shall exclude the following:

                          (i)     leasing commissions, attorneys' fees, costs
         and disbursements and other expenses incurred in connection with
         leasing,(29) renovating or improving space for tenants or prospective
         tenants of the Building;

                          (ii)    costs (including permit, license and
         inspection fees) incurred in renovating or otherwise improving or
         decorating, painting or redecorating space for tenants or vacant
         space;

                          (iii)   Landlord's costs of any services sold to
         tenants for which Landlord is entitled to be reimbursed by such
         tenants as an additional charge or rental over and above the Basic
         Rental and Actual Operating Expenses payable under the lease with such
         tenant or other occupant;

                          (iv)    any depreciation and amortization on the
         Building except as expressly permitted herein;

                          (v)     costs incurred due to violation by Landlord
         of any of the terms and conditions of this Lease or any other lease
         relating to the Building;

                          (vi)    interest on debt or amortization payments on
         any mortgages or deeds of trust or any other debt for borrowed money;

                          (vii)   all items and services for which Tenant
         reimburses Landlord outside of Actual Operating Expenses or pays third
         persons or which Landlord provides selectively to one or more tenants
         or occupants of the Building (other than Tenant) without
         reimbursement;

                          (viii)  (30) repairs or other work occasioned by
         fire, windstorm or other work(31) insurance or condemnation proceeds;





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     29  lease disputes,

     30  the cost of

     31  to the extent such cost is reimbursed by

                                      -9-
<PAGE>   10
                          (ix)    repairs resulting from any defect in the
         original design or construction of the Building;

                          (32)





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     32          (x)      Landlord's general overhead and administrative
expenses (except as otherwise provided in Paragraph 6(c) above);

                 (xi)     Advertising and promotional expenditures in excess of
$35,000.00 per calendar year;

                 (xii)    Fees for professional services including legal,
architectural, engineering, accounting and appraisal that (i) are not directly
related to the management, operation, repair and maintenance of the Project, or
(ii) are related to the sale, leasing, attempted sale or attempted leasing of
the Project or any part thereof;

                 (xiii)   Ground lease payments, mortgage principal, interest
or other charges commonly referred to as "points" or other loan charges and
fees in connection with any financing or refinancing associated with the
Project, the land it is located on, or with respect to all or any part of
either;

                 (xiv)    The cost of any electric current other than that
furnished to the Premises or other Rentable Area of the Building for purposes
other than the operation of the Building;

                 (xv)     Except as provided in subparagraph (c)(xv) above, the
cost of any additions, repairs, alterations, changes, replacements and other
items which are not properly classified as an expense;

                 (xvi)    Any costs and expenses payable to affiliates of
Landlord to the extent such costs and expenses exceed competitive fees charged
by unaffiliated persons or entities of similar skill, competence and
reputation;

                 (xvii)   The cost of any work or service performed for or
facilities furnished to any tenant of the Building to a greater extent or in a
manner more favorable to such tenant than performed for or furnished to Tenant;

                 (xviii)  The cost of any work or service performed for any
facility other than the Project;

                 (xix)    Any expenses for repairs or maintenance related to
the Project that are reimbursed to Landlord pursuant to warranties or service
contracts;

                 (xx)     Any costs, penalties and fines including interest
thereon incurred due to the violation by Landlord of any building codes, or any
other governmental rule or requirement pertaining to the Building, except such
as may be incurred by Landlord in contesting in good faith the alleged
violation;

                 (xxi)    Interest and penalties due to late payment of taxes
payable by Landlord, except such as may be incurred by Landlord in contesting
in good faith the payment of such taxes; and

                 (xxii)   Interest upon the undepreciated (or unamortized)
balance of the original cost of items which Landlord is entitled to depreciate
(or amortize) as an Actual Operating Expense.

                                      -10-
<PAGE>   11
                 (e)      Credits.  Landlord will credit against Actual
         Operating Expenses any refunds received as a result of tax contests,
         after deduction for Landlord's costs in connection with same.

                 (f)      Discretionary Items.  The foregoing provisions of
         this Paragraph 6 will not be deemed to require Landlord to furnish or
         cause to be furnished any service or facility not otherwise required
         to be furnished by Landlord pursuant to the provisions of this Lease,
         although Landlord, in Landlord's absolute discretion, may choose to do
         so from time to time.

                 (g)      Estimated Actual Operating Expenses.  Landlord shall
         have the right to estimate Additional Rental to accrue hereunder and
         Tenant shall pay to Landlord one-twelfth (1/12) of the amount of such
         estimate monthly with each of Tenant's Basic Rental payments.  If
         Landlord estimates Additional Rental in advance, then by each April 1
         or as soon thereafter as practical, Landlord shall furnish to Tenant a
         statement of Landlord's Actual Operating Expenses for the previous
         calendar year.  If for any calendar year Tenant's Additional Rental
         collected for the prior year, as a result of payment of Tenant's
         estimated Additional Rental, is in excess of Tenant's Additional
         Rental actually due during such prior year, then, so long as Tenant is
         not in default hereunder, Landlord shall refund to Tenant(33) any
         overpayment(34).  Likewise, Tenant shall pay to Landlord, on demand,
         any underpayment with respect to the prior year, which obligation of
         Tenant shall survive the expiration or earlier termination of this
         Lease.

                 (h)      Energy Costs.  As additional rental, Tenant shall pay
         to Landlord along with each of Tenant's Basic Rental payments,
         Tenant's proportionate share of the(35) costs incurred by Landlord for
         (i) any and all forms of fuel or energy utilized in connection with
         the operation, maintenance, and use of the Project, (ii) sales, use,
         excise and other taxes assessed by governmental authorities on energy
         sources supplied to the Project, and (iii) other(36) costs of
         providing energy to the Project.  Tenant's proportionate share shall
         be based on the ratio which the Rentable Area in the Premises
         (adjusted for office expansions(37)) bears to the number of square feet
         of all Rentable Area occupied by tenants in the Building from time to
         time.  Landlord shall have the





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     33  within thirty (30) days

     34  , which obligation shall survive the expiration or earlier termination
of this Lease

     35  actual

     36  actual

     37  , and excluding the Rentable Area of that portion of the Premises
which is separately metered

                                      -11-
<PAGE>   12
         right to estimate such energy costs in the same manner as the
         estimation of Actual Operating Expenses pursuant to Paragraph 6(g)
         above.

                 (38)

         7.      LANDLORD'S OBLIGATIONS.

                 (a)      Water, Heat, Air Conditioning, Janitorial and
         Elevator Service and Maintenance Obligations.  Subject to the
         limitations hereinafter set forth, Landlord agrees to furnish Tenant
         while occupying the Premises and while Tenant is not in default under
         this Lease: (i) water (hot and cold) at those points of supply
         provided for general use of tenants of the Building; (ii) Building
         Standard heat and air conditioning in season, as determined by
         Landlord, weekdays (other than holidays) between 7:00 a.m. and 6:00
         p.m., and Saturdays between 8:00 a.m. and 1:30 p.m., at such
         temperatures and in such amounts as are reasonably considered by
         Landlord to be standard (Landlord shall only furnish heat and air
         conditioning weekdays after 6:00 p.m., on Saturdays after 1:30 p.m.,
         and on Sundays and holidays at the written request of Tenant (which
         must be received by Landlord at least twenty-four (24) hours in
         advance, but no later than 12:00 noon of the preceding Friday, if the
         request is for Saturday, Sunday or a holiday), and at Tenant's cost
         payable within fifteen (15) days after receipt of an invoice); (iii)
         Building Standard janitorial service on weekdays other than holidays
         for Building installations(39) and Building Standard window washing;
         (iv) operatorless passenger elevators for ingress





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     38  (i)     Right to Audit.  Tenant shall have the right, at Tenant's sole
cost and expense, for a period of sixty (60) days after Landlord delivers to
Tenant the statement of Landlord's Actual Operating Expenses for the previous
calendar year (the "Review Period") to conduct an audit of that portion of
Landlord's books and records pertaining only to the Actual Operating Expenses
for such preceding calendar year; provided that the accounting firm conducting
the audit and Tenant execute a confidentiality agreement for the benefit of
Landlord prior to the commencement of any such audit.  This paragraph shall not
be construed to limit or abate Tenant's obligation to pay the Additional Rental
when due as set forth hereinabove.  If such audit conducted by Tenant discloses
that Tenant has overpaid or underpaid Tenant's proportionate share of Actual
Operating Expenses, then, after verification of such audit by Landlord or by
accountants selected by Landlord, any overpayment shall be refunded to Tenant
(so long as Tenant is not then in default of any of the terms of this Lease, in
which event such overpayment shall be applied against any amount Tenant owes as
a result of such default) within thirty (30) days after the verification of the
audit, or any underpayment shall be paid to Landlord within thirty (30) days
after the verification of the audit.  If the audit proves that Landlord's
calculation of Tenant's Additional Rental for the calendar year under
inspection was overstated by more than five percent (5%), then, after
verification, Landlord shall pay Tenant's actual reasonable out-of-pocket audit
and inspection fees applicable to the review of said calendar year statement
within thirty (30) days after receipt of Tenant's invoice therefor.


     39  (a  copy of the current Building Standard Janitorial Services is
attached  hereto as Exhibit D, such services are subject to change by Landlord
at any time without notice to Tenant)

                                      -12-
<PAGE>   13
         and egress to the floor(s) on which the Premises are located(40); and
         (v) replacement of Building Standard fluorescent tubes, but(41).(42)
         Landlord additionally agrees to maintain in the Building the exterior
         walls, roof, windows, structural steel, load-bearing nondemising
         walls, floors below the level of Tenant's floor covering(43) and the
         HVAC, electrical and plumbing systems serving the Premises, but
         located outside the Premises, subject to the terms and conditions of
         this Lease which may limit Landlord's maintenance, repair and
         rebuilding obligations under various circumstances.(44)





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     40  , including, but not  limited to, an operatorless  passenger elevator
for  ingress and egress between  the tenth, eleventh, and twelfth floors of the
Premises

     41  the cost  of replacement  of such  tubes shall  be charged  by
Landlord  as an  Actual Operating  Expense of  the Project

     42  Notwithstanding  any provision  to the  contrary in  Paragraph
7(a)(ii) above,  Landlord  and Tenant  agree that Tenant shall install,  at
Tenant's sole cost and expense,  the equipment necessary to supply  heat, air
conditioning, and electricity  to  any  floor(s) in  the  Premises  which
requires  twenty-four (24)  hour  HVAC  service ("Tenant's  HVAC Equipment").
In addition, Landlord shall install and maintain,  at the sole cost and expense
of Tenant, a submeter which shall be  read by Landlord  and which shall
determine the amount  of electricity  consumed by Tenant  per month on  such
floor(s), and Tenant  shall pay to Landlord  monthly, upon demand, the actual
cost of such electrical service.   For the purposes hereof,  the terms  month
or  monthly shall  include any  other  billing period  used by  the utility
supplying electricity to the Building.   Landlord shall not be liable in any
way to Tenant for  any failure or defect in the supply or character of
electric energy  furnished to the  separately metered  floor(s) by  reason of
any  requirement, act,  or omission of the public utility serving the  Building
with electricity, nor shall Landlord be liable in  any way to Tenant for the
maintenance or  operation of Tenant's HVAC Equipment.  All installations  of
electrical fixtures, appliances, and equipment within  the Premises shall be
subject to Landlord's prior  approval, which approval shall  not be
unreasonably withheld, conditioned, or delayed.   If Tenant desires that
Landlord provide  such electrical services to the  separately metered floor(s)
at any time during the Lease Term, then Tenant shall design the installation
of Tenant's HVAC Equipment in such a manner so that Landlord is capable  of
providing electrical service to the separately metered floor(s), and  in such
event, Tenant shall pay to Landlord all costs associated with Landlord's supply
of such electrical power.  Landlord acknowledges that Tenant's  use of the
Premises will  require the placement of a  separate generator on a portion  of
the Project to serve  the Premises  throughout the term  of this  Lease.
Landlord agrees to  allow Tenant  to install  such generator  at Tenant's sole
cost and expense  prior to  the commencement of  the Lease Term  upon a
location  within the Project to be mutually agreed  upon by Landlord and
Tenant.   Tenant shall maintain  the generator at Tenant's sole  cost and
expense, and shall have  access to the generator at all times during the Lease
Term.  Notwithstanding anything to the contrary set forth  herein, Tenant shall
not be required to pay any additional  rental with respect to the space
utilized by the generator.  Landlord shall  have the right to relocate such
generator at any time during the term of this Lease to another area within the
Project mutually agreed upon by Landlord and Tenant, at Landlord's sole cost
and expense.

     43  , the Common Areas and the Service Areas,

     44  Landlord agrees that the above-described services and maintenance of
the Building and its components shall be comparable to services and maintenance
provided in other office buildings in the Dallas, Texas area which are
comparable in size, quality and location, throughout the Lease Term and any
renewals, extensions or expansions thereof.  Landlord has provided Tenant with
a copy of the Report of Property Condition Survey for the Project prepared by
Law Engineering, Inc., and dated December, 1995 (the "Property Condition
Report").  Except as otherwise provided in the Property Condition Report, the
HVAC, electrical and plumbing systems serving the Premises are in good working
condition on the date of execution of this Lease.

                                      -13-
<PAGE>   14
                 (b)      Electrical Service.  Tenant's use of electrical
         services furnished by Landlord shall be subject to the following:

                          (i)     * Landlord shall not be required to furnish
                 electrical current for computers, electronic data processing
                 equipment, special lighting, equipment that requires more than
                 110 volts, or any other equipment whose electrical energy
                 consumption exceeds normal office usage.(45)

                          (ii)    The amount of electricity consumed by Tenant
                 shall be determined, at the election of Landlord, either (A)
                 based upon a survey performed by a reputable consultant to be
                 selected by Landlord and paid by Tenant, or (B) through a
                 separate meter to be installed, maintained and read by
                 Landlord at the sole cost of Tenant.

                          (iii)   If(46) Tenant's requirements for or
                 consumption of electrical services(47) the usage amount
                 specified in Paragraph 7(b)(i) hereof, then(48) subject to the
                 following terms:

                                  (A)      Tenant shall pay for all costs of
                          installation and maintenance of submeters, wiring,
                          air conditioning and other items required by
                          Landlord, in Landlord's discretion, to accommodate
                          Tenant's excess design loads and capacities.





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     *   Except as otherwise provided herein,

     45  Landlord acknowledges that Tenant will require excess electrical
service in all or a portion of the Premises.  Landlord agrees to inform Tenant,
in connection with the approval of the Preliminary Plans (as such term is
defined in the Construction Agreement), if Tenant's electrical requirements
will exceed normal office usage.  In the event that Tenant's electrical
requirements exceed normal office usage, Landlord will furnish such excess
electrical current to Tenant pursuant to the terms and conditions of Paragraph
7(b)(iii) below.

     46  , during  the approval of the  Preliminary Plans for the  Premises (as
such term  is defined in the  Construction Agreement attached hereto as Exhibit
C), Landlord determines that

     47  will exceed

     48  Landlord agrees to furnish such excess electrical current to Tenant

                                      -14-
<PAGE>   15
                                  (B)      Tenant shall pay to Landlord, upon
                          demand, the(49) cost of the excess demand and
                          consumption of electrical service at rates(50) by
                          Landlord which shall be in accordance with any
                          Applicable Laws.

                                  (C)

                 (c)      Interruption of Services.  Failure to any extent to
         make available, or any slow-down, stoppage or interruption of any
         services described in this Paragraph 7 resulting from any cause
         whatsoever (other than Landlord's gross negligence(51)) shall not 

         render Landlord liable in any respect for damages, nor be construed as
         an eviction of Tenant, nor relieve Tenant from fulfillment of any
         covenant or agreement hereof.  Should any service being furnished by
         Landlord be interrupted for any cause whatsoever, Tenant shall notify
         Landlord(52) and Landlord shall use reasonable diligence to restore
         such service promptly.(53)
        




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     49  actual

     50  paid

     51  or willful misconduct

     52  in writing

     53  Tenant shall be entitled to an equitable diminution of rent based upon
the pro rata portion of the Premises which is rendered unfit for occupancy for
the Permitted Use, if such interruption of service continues for more than five
(5) consecutive business days.  Such equitable diminution of rent shall
commence on the sixth business day of such interruption and shall constitute
Tenant's sole and exclusive remedy in the event of any such occurrence, except
as otherwise set forth herein.  Notwithstanding anything in this Lease to the
contrary, in addition to Tenant's foregoing rights, in the event of a failure
by Landlord (except due to Tenant's negligence, gross negligence or willful
misconduct) for any reason to provide any of the services described in
Paragraphs 7(a)(i) (other than supply of heated water), 7(a)(ii), 7(a)(iv), or
7(b)(i), and if such failure (the "Services Failure") should continue beyond a
period of sixty (60) days (or such longer period as is reasonably necessary to
remedy such Services Failure, provided Landlord shall continuously and
diligently pursue such remedy at all times until such Services Failure is
cured), Tenant shall have the right to deliver a written notice thereof (the
"Services Notice") to Landlord (with a copy of said notice being sent
simultaneously therewith to Landlord's mortgagee in accordance with Paragraph
13(e) hereof).  If such Services Failure shall continue uncured by Landlord and
Landlord's mortgagee for an additional thirty (30) days after the receipt of
the Services Notice, Tenant shall have the right to cure such Services Failure,
and Landlord shall reimburse Tenant (which reimbursement Tenant may effect
through the withholding of rent) for all reasonable sums expended in so curing
such failure.  In the event Tenant undertakes to correct or cure the Services
Failure, Tenant shall indemnify, defend and hold Landlord harmless from and
against any loss, costs, claim, expense or liability arising out of the actions
of Tenant or its contractors, agents or employees.  The foregoing rental
abatement and self-help (and offset) rights of Tenant for a Services Failure
shall constitute Tenant's sole and exclusive remedies involving or with respect
to a Services Failure, unless such Services Failure is due to the gross
negligence or willful misconduct of Landlord.  Tenant agrees there shall be no
abatement of rent, nor shall Tenant have the right to avail itself of self-help
(and offset) rights, on account of a Services Failure due to Tenant's
negligence, gross negligence or willful misconduct.  The foregoing self-help
and offset rights (but not the abatement right) of Tenant for a Services
Failure shall be personal solely to PageMart Wireless, Inc., and shall not be
available to any assignee or sublessee, other than a Fortune 500 company or an
Affiliate (as hereinafter defined).

                                      -15-
<PAGE>   16
                 (d)      Discontinuance of Service.  Landlord reserves the
         right, upon not less than thirty (30) days written notice to Tenant,
         to discontinue the availability of electrical service to the Premises.
         If Landlord elects such option, Tenant will contract directly with
         such public utility for the continuance of service to the Premises.

         8.      TENANT'S COVENANTS.  Tenant covenants and agrees as follows:

                 (a)      Alterations.  Tenant shall make no alterations,
         changes or improvements to the Premises without first submitting to
         Landlord plans and specifications and obtaining the prior written
         consent of Landlord(54).  All work done by Tenant shall be performed in
         a good and workmanlike manner by a contractor approved by Landlord, in
         compliance with Applicable Laws and at such times and in such manner
         as not to cause interference with construction in progress or with
         other tenants in the Building.(55)





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     54  , which consent shall not be unreasonably withheld provided:  (i)
Tenant notifies Landlord in writing and furnishes Landlord with complete plans
and specifications of all such alterations, changes or improvements
(collectively, "Modifications") at least ten (10) days prior to undertaking
them, (ii) Tenant agrees to provide Landlord with "record" plans and
specifications related to such Modifications upon completion of same, (iii)
such Modifications are not visible from the exterior of the Premises or the
Building, (iv) such Modifications are completed in compliance with all
Applicable Laws and do not adversely affect the mechanical, electrical or
plumbing systems or the structural integrity of the Building, and (v) Tenant
coordinates the construction of such Modifications with the Building's property
manager.  Notwithstanding the foregoing, Landlord's prior written consent shall
not be required for work to the interior of the Premises (hereinafter referred
to as "Cosmetic Work") which (i) is not visible from and does not affect the
exterior of the Premises or the Building, (ii) is completed in accordance with
all Applicable Laws, and (iii) does not adversely affect the mechanical,
electrical or plumbing systems or the structural integrity of the Building, so
long as Tenant provides advance written notice to Landlord of such Cosmetic
Work.  Landlord shall, at the written request of Tenant, indicate whether such
alterations, changes or improvements must be removed by Tenant upon the
expiration or termination of this Lease.  Tenant agrees that the Modifications
and Cosmetic Work shall be completed at Tenant's sole cost and expense

     55  Notwithstanding the foregoing, Landlord's approval of the contractor
performing the work shall not be required so long as (i) the work is purely
Cosmetic Work to the interior of the Premises, and (ii) the contractor is
experienced, licensed, insured, and bonded.

                                      -16-
<PAGE>   17
                 (b)      Mechanic's and Materialmen's Liens.  Tenant shall
         have no authority or power, express or implied, to create or cause any
         mechanic's or materialmen's lien, charge or encumbrance of any kind
         against the Premises or the Project or any portion thereof.  Tenant
         shall promptly cause any such liens which have arisen by reason of any
         work or materials claimed to have been provided to or undertaken by or
         through Tenant to be released by payment, bonding or otherwise within
         thirty (30) days after request by Landlord, and Tenant shall indemnify
         Landlord against losses arising out of any such claim.  Tenant's
         indemnification of Landlord contained in this Paragraph 8(b) shall
         survive the expiration or earlier termination of this Lease.

                 (c)      Permitted Use of Premises.  Tenant shall not permit
         the Premises to be used for any purpose other than for the use
         specified in Paragraph 1 of this Lease.  Tenant will, at Tenant's sole
         cost, promptly comply with all Applicable Laws(56).  The judgment of
         any court of competent jurisdiction or the admission of Tenant in any
         action against Tenant, whether Landlord is a party thereto or not,
         that Tenant has violated any Applicable Law will be conclusive of that
         fact between Landlord and Tenant.  Tenant will conduct its business
         and occupy the Premises and will control its agents, employees,
         licensees and(57) invitees in such a manner so as not to create any
         nuisance or interfere with, annoy or disturb any of the other tenants
         in the Building or Landlord in its management of the Building and so
         as not to injure the reputation of the Building.

                 (d)      Repairs.  Tenant will not in any manner deface or
         injure the Building, and will pay the cost of repairing and replacing
         any damage or injury done to the Building or any part thereof by
         Tenant or Tenant's agents, contractors or employees(58).  Tenant shall
         throughout the Lease Term keep the Premises free from deterioration,
         waste and nuisance of any kind, excluding (i) ordinary and customary
         wear and tear, and (ii) damage resulting from a fire or other
         casualty.  Tenant agrees to keep the Premises in good condition and
         repair and Tenant shall make all necessary repairs and
         replacements(59).  If Tenant fails to make such repairs or
         replacements within fifteen (15) days after notice from Landlord,
         Landlord may at its option make such repairs or replacements, and
         Tenant shall upon demand pay Landlord for the cost thereof.





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     56  , except to the  extent that the Applicable Laws apply  to obligations
and responsibilities of Landlord  pursuant to the terms of this Lease

     57  will use its best efforts to control its

     58  to the  extent  such  damage or  injury  is not  covered by  the
insurance maintained  by  Landlord pursuant  to Paragraph 10 of this Lease

     59  for which Tenant is responsible pursuant to the terms of this Lease

                                      -17-
<PAGE>   18
                 (e)      Security.  Tenant shall take all reasonable steps
         necessary to adequately secure the Premises from unlawful intrusion,
         theft, fire and other hazards, and shall keep and maintain all
         security devices in or on the Premises in good working order,
         including, but not limited to, locks, smoke detectors and burglar
         alarms, and shall cooperate with Landlord and other tenants in the
         Building with respect to Building security matters.

         9.      ASSIGNMENT AND SUBLETTING.

                 (a)      Assignment and Subletting.  Tenant shall not sublet
         the Premises in whole or in part or market the Premises for sublease
         and shall not sell, assign or in any manner transfer this Lease or any
         interest herein, directly or indirectly (by transfer of control of
         Tenant, for example), or voluntarily or by operation of law or
         otherwise, or permit any transfer of Tenant's interest created hereby,
         or allow any lien upon Tenant's interest by operation of law or
         otherwise, or permit the use or occupancy of the Premises or any part
         thereof, by anyone other than Tenant, nor shall Tenant sublease space
         in the Building from another tenant thereof, without Landlord's prior
         written consent(60). (61)
                                             




__________________________________

     60  , which consent shall not be unreasonably withheld or delayed so long
as (i) the assignee's or sublessee's financial condition is reasonably
satisfactory to Landlord, in that such assignee's or sublessee's financial
statements indicate the ability to pay all of such party's obligations under
the proposed assignment or sublease, as applicable; (ii) the assignee or
sublessee has a net worth of at least $5,000,000.00; (iii) the assignee's or
sublessee's use of the Premises complies with the Permitted Use provisions
hereof; (iv) the assignee or sublessee does not have a bad or negative
reputation in the business community; (v) the proposed assignment or sublease
will not have an adverse effect on the real estate investment trust
qualification tests applicable to Landlord and its affiliates; (vi) Tenant is
not in default under the Lease at the time of such assignment or subletting;
and (vii) Tenant shall remain liable for the performance of each and every
term, covenant and condition hereof, as the same may be amended from time to
time

     61  Notwithstanding the foregoing, Tenant may assign this Lease to an
Affiliate (as hereinafter defined) without the prior written consent of
Landlord, provided that (i) such assignee's use of the Premises complies with
the Permitted Use provisions hereof; (ii) assignee does not have a bad or
negative reputation in the business community; (iii) Tenant notifies Landlord
in advance of such assignment, which notice shall include the identity of such
assignee; (iv) such assignee has a net worth at the time of such assignment of
not less than $5,000,000.00; (v) such assignee agrees in writing to assume and
fully perform and observe the obligations and agreements of Tenant under this
Lease; (vi) Tenant is not in default under the Lease at the time of such
assignment; and (vii) Tenant remains liable for the performance of each and
every term, covenant and condition hereof, as the same may be amended from time
to time.  Any permitted assignment of Tenant's interest in this Lease shall not
become effective until an assumption agreement is executed by the permitted
assignee, including an Affiliate, which assumption agreement shall be approved
by Landlord and promptly delivered to Landlord following the execution thereof.
As used herein, "Affiliate" means any person or entity controlling, controlled
by or under common control with Tenant.  "Control" as used herein means the
power, directly or indirectly, to direct or cause the direction of the
management and policies of the controlled person or entity.  The ownership,
directly or indirectly, of at least fifty-one percent (51%) of the voting
securities of, or the possession of the right to vote in the ordinary direction
of its affairs at least fifty-one percent (51%) of the voting interest in, any
person or entity shall be presumed to constitute such control.  In addition to
the foregoing, Tenant may assign this Lease to a Fortune 500 company, without
the prior written consent of Landlord, provided that (i) such assignee's use of
the Premises complies with the Permitted Use provisions hereof; (ii) Tenant
notifies Landlord in advance of such assignment, which notice shall include the
identity of such assignee; (iii) Tenant is not in default under the Lease at
the time of such assignment; and (iv) such assignee agrees in writing to assume
and fully perform and observe the obligations and agreements of Tenant under
this Lease.  Any permitted assignment of Tenant's interest in this Lease to a
Fortune 500 company shall not become effective until an assumption agreement is
executed by the Fortune 500 company, which assumption agreement shall be
approved by Landlord and promptly delivered to Landlord following the execution
thereof.  Upon delivery to Landlord of an assumption agreement executed by the
Fortune 500 company, Tenant shall be released from liability for the
performance of the terms, covenants and conditions of this Lease, as the same
may be amended from time to time.

                                      -18-
<PAGE>   19
         If this Lease or any interest in this Lease is sold, assigned or
         transferred, or Tenant subleases any part of the Premises, without
         Landlord's consent, Landlord may, cumulative of any other right or
         remedy available to Landlord, elect to terminate this Lease (as it
         affects the portion of the Premises sought to be sublet or assigned)
         as of the effective date of the proposed transfer.  Landlord's
         acceptance of any name for listing on the Building directory will not
         be deemed, nor will it substitute for, Landlord's consent, as required
         by this Lease, to any sublease, assignment or other occupancy of the
         Premises.

                 (b)      Consent to Assignment.  Consent by Landlord to one or
         more assignments or sublettings shall not operate as a waiver of
         Landlord's rights as to any subsequent assignments and
         sublettings. (62)any assignment or subletting, Tenant  shall at all
         times remain fully responsible and liable for the payment of the rent
         and other sums herein specified and for compliance with all of
         Tenant's other obligations under this Lease, and Landlord may proceed
         against Tenant  for the enforcement of such obligations without first
         proceeding against any other party.  No direct collection by Landlord
         from any such assignee or sublessee shall be construed to constitute a
         novation or a release of Tenant  from the further performance of its
         obligations hereunder.  If the proposed sublessee or assignee is
         subject to compliance with additional requirements under The Americans
         with Disabilities Act beyond those requirements which are applicable
         to the Tenant desiring to sublet or assign, Landlord may condition
         Landlord's consent upon receipt of (i) plans and specifications
         acceptable to Landlord for complying with the additional requirements,
         and (ii) security acceptable to Landlord that such construction will
         be completed timely and lien-free.  In addition, any rights which
         Tenant may have relating to the renewal or extension of the Lease or
         the expansion of the Premises, if any, are personal to Tenant and
         shall not be available to any proposed or actual sublessee, assignee
         or transferee(63).





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     62  Except as otherwise expressly provided herein, notwithstanding

     63  , other than a Fortune 500 company or an Affiliate, if any

                                      -19-
<PAGE>   20
                 (c)      Excess Rents.  If any rents or other sums received by
         Tenant under any sublease are in excess of the rent and other sums
         payable by Tenant under this Lease (prorated for a sublease of less
         than one hundred percent (100%) of the Premises), or if any additional
         consideration is paid to Tenant by any assignee under any assignment,
         then such excess rents under any sublease or such additional
         consideration under any assignment (64) shall be paid by Tenant to
         Landlord as additional rent hereunder within ten (10) days after
         Tenant receives the same.  Tenant will exercise its best efforts to
         structure any sublease or assignment so that the portion of the excess
         rents which become payable to Landlord will not have an adverse effect
         on the real estate investment trust qualification tests applicable to
         Landlord and its affiliates.

                 (d)      Landlord's Right to Transfer.  Landlord shall have
         the right to transfer, assign and convey, in whole or in part, the
         Building and any and all of its rights under this Lease, and in such
         event, Landlord shall thereby be released from any further obligations
         hereunder(65), and Tenant agrees to look solely to such
         successor-in-interest of Landlord for performance of such obligations.

         10.     INDEMNITY AND INSURANCE.

                 (a)      (66)Indemnity(67). (68)Tenant hereby agrees to
         indemnify, protect, defend and hold harmless Landlord and its
         partners, affiliated companies, officers, directors, shareholders,
         employees and agents (collectively, "Landlord Indemnitees") for, from
         and against all liabilities, claims, fines, penalties, costs, damages
         or injuries to persons, damages to property, losses, liens, causes of
         action, suits, judgments and expenses (including court costs,
         attorneys' fees and costs of investigation), of any nature, kind or
         description of any person or entity, directly or indirectly arising
         out of, caused by, or resulting from (in whole or part)(69) Tenant's
         construction of or use, occupancy or





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     64  (after deducting therefrom all expenses and concessions or inducements
(excluding Tenant's internal overhead and administrative and legal expenses)
incurred or provided by Tenant in connection with such assignment or sublease)


     65  (except for any obligations  accruing prior to such  transfer which
are  not expressly assumed by  the successor- in-interest of Landlord)

     66  (i)

     67  of Landlord by Tenant

     68  Subject to the provisions of Paragraph 10(c) of this Lease,

     69  (A)

                                      -20-
<PAGE>   21
         enjoyment of the Premises,(70) any activity, work or other things
         done, permitted or suffered by Tenant and its agents and employees in
         or about the Premises,(71) any breach or default in the performance of
         any obligation on Tenant's part to be performed under the terms of
         this Lease including, but not limited to, Tenant's security
         obligations set forth in Paragraph 8(f) of this Lease,(72) any act,
         omission, negligence or willful misconduct of Tenant or any of its
         agents, contractors, employees, business invitees or licensees, or(73)
         damage to Tenant's property, or the property of Tenant's agents,
         employees, contractors, business invitees or licensees, located in or
         about the Premises (collectively, "Tenant Liabilities"), EVEN IF SUCH
         TENANT LIABILITIES ARE CAUSED SOLELY OR IN PART BY THE NEGLIGENCE OF
         LANDLORD OR ANY OTHER LANDLORD INDEMNITEE, BUT NOT IF SUCH TENANT
         LIABILITIES ARE CAUSED BY THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT
         OF LANDLORD OR ANY OTHER LANDLORD INDEMNITEE.  Tenant shall promptly
         advise Landlord in writing of any action, administrative or legal
         proceeding or investigation as to which this indemnification may
         apply, and Tenant, at Tenant's expense, shall assume on behalf of
         Landlord (and the other Landlord Indemnitees) and conduct with due
         diligence and in good faith the defense thereof with counsel
         satisfactory to Landlord; provided, however, that any Landlord
         Indemnitee shall have the right, at its option, to be represented
         therein by advisory counsel of its own selection and at its own
         expense.  In the event of failure by Tenant to fully perform in
         accordance with this Paragraph 10(a), Landlord, at its option, and
         without relieving Tenant of its obligations hereunder, may so perform,
         but all costs and expenses so incurred by Landlord in that event shall
         be reimbursed by Tenant to Landlord, together with interest on the
         same from the date any such expense was paid by Landlord until
         reimbursed by Tenant, at the rate of interest provided to be paid on
         judgments, by the law of the jurisdiction to which the interpretation
         of this Lease is subject.  This indemnification shall not be limited
         to damages, compensation or benefits payable under insurance policies,
         workers' compensation acts, disability benefit acts or other
         employees' benefit acts and shall survive the expiration or earlier
         termination of this Lease.

                 (74)





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     70  (B)

     71  (C)

     72  (D)

     73  (E)

     74          (ii)     Indemnity of Tenant by Landlord.  Subject to the
provisions of Paragraph 10(c) of this Lease, Landlord hereby agrees to
indemnify, protect, defend and hold harmless Tenant and its partners, officers,
directors, shareholders, employees and agents (collectively, "Tenant
Indemnitees") for, from and against all liabilities, claims, fines, penalties,
costs, damages to persons, damages to property, losses, liens, causes of
action, suits, judgments and expenses (including court costs, attorneys' fees
and costs of investigation), of any nature, kind or description of any person
or entity, directly or indirectly arising out of, caused by, or resulting from
(in whole or part) (A) any activity, work or other things done, permitted or
suffered by Landlord and its agents and employees in or about the Common Areas,
(B) any breach or default in the performance of any obligation on Landlord's
part to be performed under the terms of this Lease, or (C) any gross negligence
or willful misconduct of Landlord or any of its agents, contractors, employees,
business invitees or licensees (collectively, "Landlord Liabilities"), EVEN IF
SUCH LANDLORD LIABILITIES ARE CAUSED SOLELY OR IN PART BY THE NEGLIGENCE OF
TENANT OR ANY OTHER TENANT INDEMNITEE, BUT NOT IF SUCH LIABILITIES ARE CAUSED
BY THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF TENANT OR ANY OTHER TENANT
INDEMNITEE.  Landlord shall promptly advise Tenant in writing of any action,
administrative or legal proceeding or investigation as to which this
indemnification may apply, and Landlord, at Landlord's expense, shall assume on
behalf of Tenant (and the other Tenant Indemnitees) and conduct with due
diligence and in good faith the defense thereof; provided, however, that any
Tenant Indemnitee shall have the right, at its option, to be represented
therein by advisory counsel of its own selection and at its own expense.  In
the event of failure by Landlord to fully perform in accordance with this
indemnification paragraph, Tenant, at its option, and without relieving
Landlord of its obligations hereunder, may so perform, but all costs and
expenses so incurred by Tenant in that event shall be reimbursed by Landlord to
Tenant, together with interest on the same from the date any such expense was
paid by Tenant until reimbursed by Landlord, at the rate of interest provided
to be paid on judgments, by the law of the jurisdiction to which the
interpretation of this Lease is subject.  This indemnification shall not be
limited to damages, compensation or benefits payable under insurance policies,
workers' compensation acts, disability benefit acts or other employees' benefit
acts, but shall be limited by the provisions of Paragraph 19(c) hereof.

                                      -21-
<PAGE>   22
                 (b)      Insurance.

                          (i)     (75)  Tenant at all times during the Lease
                 Term shall, at its own expense, keep in full force and effect
                 (A) commercial general liability insurance providing coverage
                 against bodily injury and disease, including death resulting
                 therefrom, personal injury and property damage to a combined
                 single limit of $3,000,000 to one or more than one person as
                 the result of any one accident or occurrence, which shall
                 include provision for contractual liability coverage insuring
                 Tenant for the performance of its indemnity obligations set
                 forth in Paragraphs 10(a) and 18 of this Lease, (B) worker's
                 compensation insurance to the statutory limit and employer's
                 liability insurance to the limit of $500,000 per occurrence,
                 and (C) all risk personal property insurance covering full
                 replacement value of all of Tenant's personal property.
                 Landlord shall be named an additional insured on each of said
                 policies (excluding the worker's compensation policy) and said
                 policies shall be issued by an insurance company or
                 companies(76) acceptable to Landlord.  Each of said policies
                 shall also include a waiver of subrogation provision or
                 endorsement in favor of Landlord, and an endorsement providing





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     75  Tenant's Insurance.

     76  reasonably

                                      -22-
<PAGE>   23
                 that Landlord shall receive ninety (90) days prior notice of
                 any cancellation of, non-renewal of, reduction of coverage or
                 material change in coverage on said policies.  Tenant hereby
                 waives its right of recovery(77) of any amounts paid by Tenant
                 or on Tenant's behalf to satisfy applicable worker's
                 compensation laws.  The policies or duly executed certificates
                 for the same, together with satisfactory evidence of the
                 payment of the premiums therefor, shall be deposited with
                 Landlord on the date Tenant first occupies the Premises and
                 upon renewals of such policies not less than fifteen (15) days
                 prior to the expiration of the term of such coverage.

                          (ii)    It is expressly understood and agreed that
                 the coverages required represent Landlord's minimum
                 requirements and such are not to be construed to void or limit
                 Tenant's indemnity obligations contained in this Lease.
                 Neither shall (A) the insolvency, bankruptcy or failure of any
                 insurance company carrying Tenant, (B) the failure of any
                 insurance company to pay claims occurring nor (C) any
                 exclusion from or insufficiency of coverage be held to affect,
                 negate or waive any of Tenant's indemnity obligations under
                 Paragraphs 10(a) and 18 or any other provision of this Lease.
                 With respect to insurance coverages, except worker's
                 compensation, maintained hereunder by Tenant and insurance
                 coverage separately obtained by Landlord, all insurance
                 coverages afforded by policies of insurance maintained by
                 Tenant shall be primary insurance as such coverages apply to
                 Landlord, and such insurance coverages separately maintained
                 by Landlord shall be excess, and Tenant shall have its
                 insurance policies endorsed to reflect that policies
                 maintained by Tenant naming Landlord as an additional insured
                 are primary, and policies separately maintained by Landlord
                 are excess.  The amount of liability insurance under insurance
                 policies maintained by Tenant shall not be reduced by the
                 existence of insurance coverage under policies separately
                 maintained by Landlord.  Tenant shall be solely responsible
                 for any premiums, assessments, penalties, deductible
                 assumptions, retentions, audits, retrospective adjustments or
                 any other kind of payment due under its policies.

                          (iii)   Tenant's occupancy of the Premises without
                 delivering the certificates of insurance shall not constitute
                 a waiver of Tenant's obligations to provide the required
                 coverages.  If Tenant provides to Landlord a certificate that
                 does not evidence the coverages required herein, or that is
                 faulty in any respect, such shall not constitute a waiver of
                 Tenant's obligations to provide the proper insurance.





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     77  from Landlord

                                      -23-
<PAGE>   24
                          (78)

                 (c)      Mutual Waivers of Recovery.  It is the intent of
         Landlord and Tenant not to hold each other responsible for that
         portion of any loss or damage paid or reimbursed by an insurer of
         Landlord or Tenant under any fire, extended coverage or other property
         insurance policy maintained by Tenant with respect to its Premises or
         by Landlord with respect to the(79).  Therefore, with respect to the
         amount of any damage, loss, claim or liability paid or reimbursed by
         an insurer under any fire, extended coverage or property insurance
         policy maintained by Tenant with respect to the Premises, or Landlord
         with respect to the(80), Landlord, Tenant and all parties claiming
         under them each mutually release and discharge each other from such
         damages, losses, claims or liabilities, no matter how caused,
         including negligence, and each waives any right of recovery from the
         other including, but not limited to, claims for contribution or
         indemnity, which might otherwise exist on account thereof.  Any fire,
         extended coverage or property insurance policy maintained by Tenant
         with respect to the Premises, or Landlord with respect to the(81),
         shall contain, in the case of Tenant's policies, a waiver of
         subrogation provision or endorsement in favor of Landlord, and in the
         case of Landlord's policies, a waiver of subrogation provision or
         endorsement in favor of





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     78  (iv)    Landlord's Insurance.

                 (A)      Landlord shall, at its own cost and expense, keep in
         full force and effect commercial general liability insurance covering
         the Project, insuring against claims for personal or bodily injury or
         death or property damage caused by the negligence of Landlord
         occurring upon, in or about the Project to afford protection to the
         limit of not less than $1,000,000 combined single limit with respect
         to injury or death to any number of persons and property damage
         arising out of any one occurrence.  This insurance coverage shall
         extend to any liability of Landlord arising out of the indemnities
         provided for in this Lease.

                 (B)      Landlord shall, at its own cost and expense, keep in
         full force and effect a policy or policies of "all risk" property
         insurance covering the Project (excluding property required to be
         insured by Tenant) endorsed to provide replacement cost coverage up to
         policy limits in providing protection against perils included within
         the applicable standard form of fire and extended coverage insurance
         policy, together with insurance against sprinkler damage, vandalism,
         malicious mischief, and such risks as Landlord may from time to time
         determine, and with any such deductibles as Landlord may from time to
         time determine.

                 (C)      Any insurance provided for in this subparagraph may
         be effected by a policy or policies of blanket insurance covering
         additional items or locations or assureds, provided that the
         requirements of this subparagraph are otherwise satisfied.  Tenant
         shall have no rights in any policy or policies maintained by Landlord.

     79  Project

     80  Project

     81  Project

                                      -24-
<PAGE>   25
         Tenant, or, in the event that such insurers cannot or will not include
         or attach such waiver of subrogation provision or endorsement, Tenant
         and Landlord shall obtain the approval and consent of their respective
         insurers, in writing, to the terms of this Lease.  Neither Tenant nor
         its insurers shall be entitled to receive any contribution from any
         insurance policies separately maintained by Landlord, and Tenant
         agrees to indemnify, protect, defend and hold harmless Landlord and
         any of Landlord's insurers from any claim, suit or cause of action
         asserted or brought by Tenant's insurers for, on behalf of, or in the
         name of Tenant, including but not limited to, claims for contribution,
         indemnity or subrogation.(82)  The mutual releases, discharges and
         waivers contained in this provision shall apply EVEN IF THE LOSS OR
         DAMAGE TO WHICH THIS PROVISION APPLIES IS CAUSED SOLELY OR IN PART BY
         THE NEGLIGENCE OF LANDLORD OR TENANT.

                 (d)      Business Interruption.  Landlord shall not be
         responsible for, and Tenant releases and discharges Landlord from, and
         Tenant further waives any right of recovery from Landlord for, any
         loss from business interruption or loss of use of the Premises
         suffered by Tenant in connection with Tenant's use or occupancy of the
         Premises, EVEN IF SUCH LOSS IS CAUSED SOLELY OR IN PART BY THE
         NEGLIGENCE OF LANDLORD.

                 (e)      Adjustment of Claims.  Tenant shall cooperate with
         Landlord and Landlord's insurers in the adjustment of any insurance
         claim pertaining to the Building or Landlord's use thereof.(83)

                 (f)      Increase in Landlord's Insurance Costs.  Tenant
         agrees to pay to Landlord any increase in premiums for Landlord's
         insurance policies resulting from Tenant's use or occupancy of the
         Premises.

                 (g)      Failure to Maintain Insurance.  Any failure of
         Tenant(84) to obtain and maintain the insurance policies and coverages
         required hereunder or failure by Tenant(85)





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     82  Neither Landlord nor its insurers shall be entitled to receive any
contribution from any insurance policies separately maintained by Tenant, and
Landlord agrees to indemnify, protect, defend and hold harmless Tenant and any
of Tenant's insurers from any claim, suit or cause of action asserted or
brought by Landlord's insurers for, on behalf of, or in the name of Landlord,
including but not limited to, claims for contribution, indemnity or
subrogation.

     83  Landlord shall cooperate with Tenant and Tenant's insurers in the
adjustment of any insurance claim pertaining to the Premises and Tenant's use
thereof.

     84  or Landlord

     85  or Landlord

                                      -25-
<PAGE>   26
         to meet any of the insurance requirements of this Lease shall
         constitute a material breach hereof(86) shall entitle Landlord to
         pursue, exercise or obtain any of the remedies provided for in
         Paragraph 13, and Tenant shall be solely responsible for any loss
         suffered by Landlord as a result of such failure.  In the event of
         failure by Tenant to maintain the insurance policies and coverages
         required by this Lease or to meet any of the insurance requirements of
         this Lease, Landlord, at its option, and without relieving Tenant of
         its obligations hereunder, may obtain said insurance policies and
         coverages or perform any other insurance obligation of Tenant, but all
         costs and expenses incurred by Landlord in obtaining such insurance or
         performing Tenant's insurance obligations shall be reimbursed by
         Tenant to Landlord, together with interest on same from the date any
         such cost or expense was paid by Landlord until reimbursed by Tenant,
         at the rate of interest provided to be paid on judgments, by the law
         of the jurisdiction to which the interpretation of this Lease is
         subject.

         11.     FIRE OR CASUALTY.  In the event that (a) the Premises or the
Building should be so damaged by fire or other casualty that rebuilding or
repairs cannot be completed within one (1) year after the date of commencement
of reconstruction, as determined by Landlord, or (b) the Premises shall be so
damaged during the last two (2) years of the Lease Term to the extent that more
than thirty percent (30%) of the area thereof is rendered untenantable,
Landlord may at its option terminate this Lease within ninety (90) days after
such damage by giving written notice to Tenant, in which event rent shall be
abated effective with the date of such damage.(87)





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     86  .  Any such failure by Tenant

     87  Tenant shall have the right to terminate this Lease following the
occurrence of a fire or other casualty under the following conditions:

                 (a)      If the time it will take to restore the Premises to
         substantially its condition immediately prior to the fire or other
         casualty will exceed two hundred seventy (270) days after the date of
         such casualty, Landlord shall give Tenant written notice thereof
         within ninety (90) days after the occurrence of the casualty, and
         Tenant shall have the option to terminate this Lease by giving
         Landlord written notice within thirty (30) days after Tenant's receipt
         of Landlord's notice.

                 (b)      If the time it takes to restore the Premises to
         substantially its condition immediately prior to the fire or other
         casualty exceeds two hundred seventy (270) days after the date of such
         casualty, Tenant shall have the option to terminate this Lease by
         giving Landlord written notice within thirty (30) days after the
         expiration of such two hundred seventy (270) day period.

                 (c)      If the parking facilities associated with the
         Building are so damaged by fire or other casualty that Landlord is
         unable to provide at least fifty percent (50%) of the parking spaces
         to which Tenant is entitled under this Lease, and if Landlord is
         unable to (i) restore the parking facilities to substantially their
         condition immediately prior to the fire or other casualty within two
         hundred seventy (270) days after the date of such casualty, and (ii)
         provide temporary alternative parking arrangements, including
         transportation which provides reasonable access to the Building,
         within a one and one-half (1.5) mile radius of the Building within
         thirty (30) days after the date of such casualty, then Tenant shall
         have the option to terminate this Lease by giving Landlord written
         notice within thirty (30) days after the expiration of such thirty
         (30) day or two hundred seventy (270) day period.  If Tenant is unable
         to use, or Landlord is unable to provide, all or a portion of the
         parking spaces to which Tenant is entitled under this Lease, Landlord
         shall abate Tenant's obligation to pay parking charges for such spaces
         for so long as Tenant does not have the use thereof.

                                      -26-
<PAGE>   27
If, following any such casualty, Landlord(88) does not terminate this Lease, or
in the event of casualty damage of a lesser extent to the Building, Landlord
shall, following receipt of insurance proceeds if such proceeds are made
available to Landlord by the holder of any mortgage encumbering the Project or
the Building, rebuild or repair the Premises or the Building to substantially
the same condition in which they were immediately prior to the happening of the
fire or other casualty, except that Landlord shall not be required to (i) spend
more than the amount of insurance proceeds actually received, or (ii) rebuild,
repair or replace any part of the furniture, equipment, fixtures and other
personal property which may have been placed by Tenant or other tenants within
the Building or the Premises.  Landlord shall allow Tenant a fair diminution of
rental during the time the Premises are unfit for occupancy, and at Landlord's
option, the Lease Term shall be extended for a period equal to the period that
the Premises are unfit for occupancy.

         12.     CONDEMNATION.  In the event that the Premises or the Building
or any part thereof shall be taken for public use or condemned under eminent
domain or conveyed under threat of such a taking or condemnation, or access to
the Premises precluded by any such event, either Landlord or Tenant may cancel
and terminate this Lease as it affects the portion of the Premises taken, or
the portion to which access is precluded, by giving notice to the other within
ten (10) days after the date on which title to the property taken vests in the
condemnor.  Notwithstanding the foregoing, Tenant may not terminate this Lease
pursuant to the preceding sentence as a result of the condemnation of the
Building or any part thereof unless such condemnation materially affects
Tenant's use of or access to the Premises.(89) If this Lease is not terminated
as to all of the Premises following any of said actual takings or conveyances
of any part of the Premises,





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     88  or Tenant

     89  In the event of a taking or condemnation which materially affects
Tenant's use of or access to more than fifty percent (50%) of the Premises,
Tenant shall have the option to terminate this Lease with respect to the entire
Premises by giving Landlord written notice within ten (10) days after the date
on which title to the property taken vests in the condemnor.  Furthermore, in
the event of a taking or condemnation of the parking facilities associated with
the Building which affects Tenant's use of or access to more than fifty percent
(50%) of the parking spaces to which Tenant is entitled under this Lease, and
in the event that Landlord is unable to provide alternative parking
arrangements, including transportation which provides reasonable access to the
Building, within a one and one-half (1.5) mile radius of the Building within
thirty (30) days after the date on which title to the property taken vests in
the condemnor, Tenant shall have the option to terminate this Lease with
respect to the entire Premises by giving Landlord written notice within sixty
(60) days after the date on which title to the property taken vests in the
condemnor.

                                      -27-
<PAGE>   28
then Landlord shall, to the extent of an equitable proportion of the award for
the portion of the Premises taken (excluding any award for land) and to the
extent such award is made available to Landlord from the holder of any mortgage
encumbering the Project or the Building, make such repairs to the Premises as
are necessary to constitute a complete architectural and tenantable unit.(90)
In the event of a partial taking or conveyance of the Premises, Landlord shall
allow Tenant a fair diminution of rental.(91) Tenant shall not be entitled to
claim, or have paid to Tenant, any compensation or damages whatsoever for or on
account of any taking or conveyance of any right, interest or estate of Tenant
under this Lease, and Tenant hereby relinquishes and assigns to Landlord any
rights to any such compensation or damages.  Tenant does not hereby waive or
release claims for moving expenses, inconvenience or business interruption
related to a condemnation of the Premises, but any such claim shall be
asserted, if at all, in a proceeding independent of Landlord's primary
condemnation suit.

         13.     DEFAULT AND REMEDIES.

                 (a)      Events of Default.  The following events shall be
         deemed to be events of default (herein so called) by Tenant under this
         Lease: (i) Tenant shall fail to pay within five (5) days of the due
         date Basic Rental, Additional Rental or any other rental or sums
         payable by Tenant hereunder;(92) (ii) Tenant shall fail to comply with
         or observe any other provision of this Lease and such failure shall
         continue for(93) days after written notice to Tenant(94) (or, in the 
         case of Tenant's failure to comply with or observe any other single
         provision of this Lease more than three (3) times during the Lease
         Term, upon the occurrence of the fourth and all subsequent such
         failures, without notice from Landlord); (iii) Tenant or any guarantor
         of Tenant's obligations hereunder shall





__________________________________

     90  If Landlord elects not to make the repairs to the Premises as
described in the immediately preceding sentence, then Landlord shall notify
Tenant of such election and Tenant shall have the option to terminate this
Lease by giving Landlord written notice within thirty (30) days after receipt
of Landlord's notice.

     91  In the event of a taking or condemnation which affects Tenant's use of
or access to all or a portion of the parking spaces to which Tenant is entitled
under this Lease and in the event that Landlord is unable to provide
alternative parking arrangements, including transportation which provides
reasonable access to the Building, within a one and one-half (1.5) mile radius
of the Building, Landlord shall abate Tenant's obligation to pay parking
charges for the affected spaces.

     92  provided, however, that the first two (2) times during any consecutive
twelve (12) month period Tenant so fails to timely pay any of such amounts,
Landlord shall provide Tenant with written notice (either by hand delivery or
by facsimile with electronic confirmation), and a period of five (5) days in
which to pay same before Tenant shall be in default hereunder;

     93  thirty (30)

     94  or, if such failure cannot be cured within such thirty (30) day period
with reasonable diligence, such failure shall continue beyond a reasonable time
not to exceed thirty (30) days, provided that Tenant has commenced curative
action within such thirty (30) day period and is diligently attempting to cure
such failure

                                      -28-
<PAGE>   29
         make a general assignment for the benefit of creditors; (iv) any
         petition shall be filed by or against Tenant or any guarantor of
         Tenant's obligations hereunder under the United States Bankruptcy
         Code, as amended, or under any similar law or statute of the United
         States or any state thereof, and such petition shall not be dismissed
         within(95) days of filing, or Tenant or any guarantor of Tenant's
         obligations hereunder shall be adjudged bankrupt or insolvent in
         proceedings filed thereunder; (v) a receiver or trustee shall be
         appointed for all or substantially all of the assets of Tenant or any
         guarantor of Tenant's obligations hereunder, and such appointment
         shall not be vacated or otherwise terminated, and the action in which
         such appointment was ordered dismissed, within(96) days of filing; (vi)
         Tenant shall fail to take possession of or shall desert, abandon or
         vacate the Premises; (vii)  or (viii) the occurrence of an event
         described in clauses (iv) or (v) of this Paragraph 13(a) (without
         regard to any cure periods contained therein) and the failure
         thereafter of Tenant (A) to timely and fully make any payment of rent
         or any other sum of money due hereunder or (B) to perform or observe
         any other covenant, condition or agreement to be performed or observed
         by it hereunder.

                 (b)      Remedies. (97)the occurrence of any event of default
         specified in this Lease, Landlord shall have the option to pursue any
         one or more of the following remedies without any notice or demand
         whatsoever and without releasing Tenant from any obligation under this
         Lease(98):

                          (i)     Landlord may enter the Premises without
                 terminating this Lease and perform any covenant or agreement
                 or cure any condition creating or giving rise to an event of
                 default under this Lease and Tenant shall pay to Landlord on
                 demand, as additional rent, the amount expended by Landlord in
                 performing such covenants or agreements or satisfying or
                 observing such condition.  Landlord or its agents or employees
                 shall have the right to enter the Premises, and such entry and
                 such performance shall not terminate this Lease or constitute
                 an eviction of Tenant.





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     95  sixty (60)

     96  sixty (60)

     97  Except as otherwise provided below, upon

     98  Notwithstanding anything to the contrary contained herein, upon the
occurrence of an event of default by Tenant based solely on Paragraph 13(a)(vi)
above, and so long as Tenant continues to comply with all other terms and
provisions of this Lease, including, but not limited to, Tenant's obligation to
pay Basic Rental, Additional Rental and all other sums payable by Tenant under
the Lease, Landlord's only remedy shall be the option to terminate Tenant's
right of possession with respect to that portion of the Premises which Tenant
has either deserted, abandoned or vacated, without terminating this Lease, in
accordance with the terms and provisions of this Paragraph 13(b).

                                      -29-
<PAGE>   30
                          (ii)    Landlord may terminate this Lease by written
                 notice to Tenant (and not otherwise) or Landlord may terminate
                 Tenant's right of possession without terminating this Lease.
                 In either of such events Tenant shall surrender possession of
                 and vacate the Premises immediately and deliver possession
                 thereof to Landlord, and Tenant hereby grants to Landlord full
                 and free license to enter the Premises, in whole or in part,
                 with or without process of law and to expel or remove Tenant
                 and any other person, firm or corporation who may be occupying
                 the Premises or any part thereof and remove any and all
                 property therefrom, using such lawful force as may be
                 necessary.

                          (iii)   In the event Landlord elects to re-enter or
                 take possession of the Premises after Tenant's default, with
                 or without terminating this Lease, Landlord may change or pick
                 locks or alter security devices and lock out, expel or remove
                 Tenant and any other person who may be occupying all or any
                 part of the Premises without being liable for any claim for
                 damages.  Notwithstanding anything to the contrary contained
                 herein or in Section 93.002 of the Texas Property Code,
                 Landlord may exercise any and all of its rights or remedies
                 under this Lease following an event of default by Tenant
                 without compliance with Section 93.002 of the Texas Property
                 Code, the benefits of which are hereby expressly waived by
                 Tenant.

                          (iv)    If Landlord elects to re-enter or take
                 possession of the Premises without terminating this Lease,
                 then Tenant shall be liable for and shall pay to Landlord all
                 Basic Rental and any other amounts of money due to Landlord
                 hereunder as of the date of such election.  Tenant shall also
                 pay to Landlord all Basic Rental required to be paid by Tenant
                 during the remainder of the Lease Term as such amounts become
                 due, diminished by any net sums received by Landlord, if any,
                 through reletting the Premises during said period (after
                 deducting all expenses incurred by Landlord in connection with
                 any reletting of the Premises).  Landlord is not obligated to
                 relet the Premises, and if no reletting occurs, Tenant shall
                 be responsible for the full amounts due.  If Landlord elects
                 to relet, Landlord shall have the sole and unfettered right to
                 relet all or any part of the Premises for such rent and upon
                 such terms as shall be satisfactory to Landlord (including but
                 not limited to the right to relet the Premises for a term
                 shorter or longer than that remaining under this Lease, the
                 right to relet the Premises as a part of a larger area and the
                 right to change the character or use made of the Premises).
                 Tenant shall not in any event be entitled to any sums
                 collected in connection with a reletting of the Premises that
                 exceed the amount of Basic Rental and other sums of money due
                 hereunder.  Landlord shall not be required to wait until the
                 expiration of the Lease Term in order to collect any such
                 deficiencies, and shall have the right to file suit from time
                 to time, on one or more occasions, to collect the deficiencies
                 then due.  Any such suit shall not





                                      -30-
<PAGE>   31
                 prejudice in any way the right of Landlord to bring similar
                 actions for any subsequent deficiency or deficiencies.

                          (v)     Notwithstanding any prior election by
                 Landlord to not terminate this Lease, Landlord may at any
                 time, including subsequent to any re-entry or taking of
                 possession of the Premises as allowed hereinabove, elect to
                 terminate this Lease.  Tenant shall be liable for and shall
                 immediately pay to Landlord the amount of all Basic Rental and
                 other sums of money due under this Lease as may have accrued
                 as of the date of termination.  Tenant shall also immediately
                 pay to Landlord, as agreed and liquidated damages, an amount
                 of money equal to the Basic Rental and other amounts due for
                 the remaining portion of the Lease Term (had such term not
                 been terminated by Landlord prior to the expiration of the
                 Lease Term), less the fair rental value of the Premises for
                 the residue of the Lease Term, both discounted to their
                 present value based upon an interest rate of eight percent
                 (8%) per annum.  In determining fair rental value, Landlord
                 shall be entitled to take into account the time and expenses
                 necessary to obtain a replacement tenant or tenants, including
                 anticipated expenses hereinafter described relating to
                 recovery, preparation and reletting of the Premises; provided,
                 however, the parties hereto stipulate and agree that the fair
                 rental value shall never be deemed to exceed eighty-five
                 percent (85%) of the Basic Rental provided for herein for said
                 residual period.  If Landlord elects to relet the Premises, or
                 any portion thereof, before presentation of proof of such
                 liquidated damages, the amount of rent reserved upon such
                 reletting shall be deemed prima facie evidence of the fair
                 rental value of the portion of the Premises so relet.

                          (vi)    In addition to any sum provided to be paid
                 above, Tenant shall also be liable for and shall immediately
                 pay to Landlord all broker's fees incurred by Landlord in
                 connection with any reletting of the whole or any part of the
                 Premises, the costs of removing and storing Tenant's or any
                 other occupant's property, the cost of repairing, altering,
                 remodeling, renovating or otherwise putting the Premises into
                 a condition acceptable to a new tenant or tenants, the cost of
                 removal and replacement of signage and all reasonable expenses
                 by Landlord in enforcing Landlord's remedies, including
                 reasonable attorneys' fees.

                          (vii)   Landlord may apply Tenant's Security Deposit
                 to the extent necessary to make good any rent arrearage, to
                 pay the cost of remedying Tenant's default or to reimburse
                 Landlord for expenditures made or damages suffered as a
                 consequence of Tenant's default.  Following any such
                 application of the Security Deposit, Tenant shall pay to
                 Landlord on demand the amount so applied in order to restore
                 the Security Deposit to its original amount.

                          (viii)  Nothing contained in this Paragraph 13(b)
                 shall be construed as imposing any enforceable duty upon
                 Landlord to relet the Premises or otherwise





                                      -31-
<PAGE>   32
                 mitigate or minimize Landlord's damages by virtue of Tenant's
                 default.  Landlord  shall not be liable in any manner, nor
                 shall Tenant's obligations hereunder be diminished, by the
                 failure of Landlord to relet the Premises, or in the event of
                 reletting to collect rent.

                 (c)      Effect of Suit or Partial Collection.  Institution of
         a forcible detainer action to re-enter the Premises shall not be
         construed to be an election by Landlord to terminate this Lease.
         Landlord may collect and receive any rent due from Tenant and the
         payment thereof shall not constitute a waiver of or affect any notice
         or demand given, suit instituted or judgment obtained by Landlord, or
         be held to waive or alter the rights or remedies which Landlord may
         have at law or in equity or by virtue of this Lease at the time of
         such payment.

                 (d)      Remedies Cumulative.  All rights and remedies of
         Landlord herein or existing at law or in equity are cumulative and the
         exercise of one or more rights or remedies shall not be taken to
         exclude or waive the right to the exercise of any other.

                 (e)      Notice to Mortgagees.  If Landlord defaults under
         this Lease and, if as a consequence of such default, Tenant will have
         the right to terminate this Lease, Tenant will not exercise such right
         to terminate unless and until (i) Tenant gives notice of such default
         (specifying the exact nature of such default and how such default may
         be remedied) to any lessor under a ground lease or any mortgagee of
         the Building, and (ii) such lessor and/or mortgagee fails to cure, or
         to cause to be cured, such default within thirty (30) days after such
         lessor's or mortgagee's receipt of notice.

                 (99)

         14.     SURRENDER OF PREMISES.

                 (a)      Surrender.  (100)the Expiration Date or earlier
         termination of this Lease, Tenant shall peaceably surrender to
         Landlord the Premises, including the alterations, improvements and
         changes (except as provided in Paragraph 14(b)) other than Tenant's
         fixtures remaining the property of Tenant, broom-clean and in the
         condition the





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     99  (f)     Landlord Defaults and Tenant Remedies.  Except as provided
otherwise in this Lease and subject to Paragraphs 13(e), 19(c) and 19(n)
hereof, if Landlord shall fail in the performance of any of Landlord's
obligations hereunder and such failure shall continue for a period of thirty
(30) days after Landlord's receipt of written notice thereof from Tenant (or an
additional reasonable time after such receipt if (i) such failure cannot be
cured within such thirty (30) day period, and (ii) Landlord commences curing
such failure within such thirty (30) day period and thereafter diligently
pursues the curing of such failure), then Tenant shall be entitled to exercise
any remedies that Tenant may have at law or in equity.

     100 Subject to the terms of Paragraph 15 hereof, upon

                                      -32-
<PAGE>   33
         same were in on the Commencement Date, subject only to (i) ordinary
         and customary wear and tear, and (ii) damage resulting from a fire or
         other casualty.

                 (b)      Removal of Alterations and Tenant's Property.

                                  (i)      (101)all permanent or built-in
                 fixtures or improvements and all mechanical, electrical and
                 plumbing equipment in the Premises shall be the property of
                 Landlord upon the termination of this Lease,(102) all
                 furnishings, equipment, furniture, trade fixtures and other
                 removable equipment installed in the Premises by Tenant  shall
                 remain the property of Tenant and shall be removed by Tenant
                 upon the expiration or termination of this Lease.  Tenant
                 shall repair any damage caused by such removal.

                                  (ii)     If any furnishings, equipment,
                 furniture, trade fixtures or other removable equipment are not
                 removed within five (5) business days after the expiration of
                 this Lease, then Tenant hereby grants to Landlord the option,
                 exercisable at any time thereafter without the requirement of
                 any notice to Tenant, (A) to treat such property, or any
                 portion thereof, as being abandoned by Tenant to Landlord,
                 whereupon Landlord shall be deemed to have full rights of
                 ownership thereof; (B) to elect to remove and store such
                 property, or any portion thereof, on Tenant's behalf (but
                 without assuming any liability to any person) and at Tenant's
                 sole cost and expense, with reimbursement therefor to be made
                 to Landlord upon demand; and/or (C) to sell, give away, donate
                 or dispose of as trash or refuse any or all of such property
                 without any responsibility to deliver to Tenant any proceeds
                 therefrom.  If(103) rights to occupy the Premises are
                 terminated by Landlord, prior to Landlord's termination or the
                 expiration of this Lease, and  any of Tenant's furnishings,
                 equipment, furniture, trade fixtures or other removable
                 equipment are not removed within five (5) business days
                 thereafter, then Tenant hereby grants to Landlord the option,
                 exercisable at any time thereafter without the requirement of
                 notice to Tenant, (x) to treat such property, or any portion
                 thereof, as being abandoned by Tenant to Landlord, whereupon
                 Landlord shall be deemed to have full rights of ownership
                 thereof; (y) to elect to remove and store such property, or
                 any portion thereof, on  Tenant's behalf (but without assuming
                 any liability to any person)





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     101 Except as otherwise provided in writing by Landlord and  Tenant, (A)

     102 and (B)

     103 Tenant's

                                      -33-
<PAGE>   34
                 and at Tenant's sole cost and expense, with reimbursement
                 therefor to be made to Landlord upon demand; and/or (z) to
                 sell, give away, donate or dispose of as trash or refuse any
                 or all of such property without responsibility to deliver to
                 Tenant any proceeds therefrom.  Landlord shall have no
                 liability of any kind whatsoever to Tenant in respect of the
                 exercise or failure to exercise the options set forth in this
                 Paragraph 14(b).  Specifically, Tenant shall not have the
                 right to assert against Landlord a claim either for the value,
                 or the use, of any such property, either as an offset against
                 any amount of money owing to Landlord or otherwise.  The
                 provisions of this Paragraph 14(b) shall supersede the
                 provisions of Section 93.002(d) and (e) of the Texas Property
                 Code, as such may be amended from time to time, and any other
                 law which purports to restrict the options granted to Landlord
                 herein.

         15.     HOLDING OVER.  If Tenant remains in possession of the Premises
after the expiration of the tenancy created hereunder and without the execution
of a new lease, Tenant shall be deemed to be occupying the Premises as a tenant
at will and subject to all of the provisions of this Lease except those
relating to term and except that the Basic Rental and Additional Rental shall
be(104) the amount payable during the last month of the Lease Term(105)
(without waiver of Landlord's right to recover damages as permitted by this
Lease or by law).  Said tenancy may be terminated by Landlord or Tenant by
giving(106) written notice to the other at any time.  Landlord's acceptance
during any such holdover period of Basic Rental and/or Additional Rental
payments from Tenant of less than the full amounts to which Landlord is
entitled under this Paragraph 15 shall not be deemed to constitute a waiver of
Landlord's right to later collect from Tenant the difference between the
amounts actually paid by Tenant and the full amounts due hereunder.

         16.     MORTGAGES.  This Lease shall be subordinate to all deeds of
trust and ground leases now or hereafter encumbering the Building, and all
refinancings, replacements, renewals, modifications, extensions or
consolidations thereof.  Tenant agrees to attorn to any mortgagee, ground
lessor, trustee under a deed of trust or purchaser at a foreclosure sale or
trustee's sale as Landlord under this Lease.  Tenant covenants and agrees that
Tenant shall within five (5) days after Landlord's request execute in
recordable form and deliver to Landlord whatever instruments may be required to
acknowledge and further evidence the subordination of this Lease





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     104 one hundred fifty percent (150%) of

     105 for the first ninety (90) days of any such holdover and double the 
amount payable during the last month of the Lease Term thereafter

     106 thirty (30) days prior

                                      -34-
<PAGE>   35
and/or the attornment by Tenant to such mortgagee, ground lessor, trustee or
purchaser.(107)  If within five (5) business days after submission of any such
instrument, Tenant fails to execute the same, Landlord is hereby authorized to
execute the same as attorney-in-fact for Tenant.  Any holder of a deed of trust
covering all or any part of the Building may at any time elect to have this
Lease have priority over its deed of trust by executing unilaterally an
instrument of subordination or placing a clause of such subordination in any
pleadings or in its deed of trust and recording the same.

         17.     CERTAIN RIGHTS RESERVED BY LANDLORD.  Landlord shall have the
                 following rights:

                 (a)      Common and Service Area Alterations.  To decorate and
         to make repairs, alterations, additions, changes or improvements,
         whether structural or otherwise, in, about or on the exterior of the
         Building, or any part thereof, and to change, alter, relocate, remove
         or replace Service Areas and/or Common Areas; to place, inspect,
         repair and replace in the Premises (below floors, above ceilings or
         next to columns) utility lines, pipes, cables and the like to serve
         other areas of the Building outside the Premises; and to otherwise
         alter or modify the Project, and for such purposes to enter upon the
         Premises and, during the continuance of any such work, to take such
         measures for safety or for the expediting of such work as may be
         required, in Landlord's judgment, all without affecting any of
         Tenant's obligations hereunder, provided Landlord's entries in the
         Premises shall be subject to the terms of Paragraph 19(l).(108)

                 (b)      Parking.  To permit Tenant and its employees to use
         the parking facilities associated with the Building only in accordance
         with rules and regulations promulgated from time to time by Landlord
         and/or the operator of the parking facilities and at such charges as
         then may be in effect; and to prohibit Tenant and its employees to use
         any on-site surface parking spaces within the Project designated for
         visitors, occupants of the Building, or otherwise.(109)  The number of
         parking spaces available for Tenant's use      





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     107 Notwithstanding the foregoing, Tenant's agreement to subordinate this
Lease and to attorn to any mortgagee, ground lessor, trustee or purchaser as
provided in this Paragraph 16 shall be contingent on Landlord obtaining a
nondisturbance agreement for the benefit of Tenant from any future holder of a
deed of trust covering all or any part of the Building.  Such nondisturbance
agreement shall be in the form required by such holder provided that such form
does not materially diminish Tenant's rights under this Lease.

     108 Landlord agrees to take such actions as may be reasonably required to
minimize interference with Tenant's access to the Building and use and occupancy
of the Premises for the Permitted Use, so long as such actions do not increase
the cost of the work performed or caused to be performed by Landlord in the
exercise of its rights under this Paragraph 17(a).

     109 Notwithstanding the foregoing, during the initial term of this
Lease, so long as Tenant is not in default hereunder, Tenant shall be permitted
to use at no charge to Tenant nonreserved parking spaces in the parking garage
associated with the Building at the ratio of one (1) parking space for every
three hundred (300) square feet of Rentable Area in the Premises.  In the event
Tenant requires additional parking spaces, Landlord agrees to use reasonable
efforts to accommodate Tenant's parking needs to the extent that available
parking spaces exist in the Building parking facilities.

                                      -35-
<PAGE>   36
         shall not exceed one (1) space for every three hundred (300) square
         feet of Rentable Area in the Premises.  Parking spaces will be
         unassigned, provided that Landlord may at any time assign parking
         spaces.  Landlord shall not be obligated to control any unauthorized
         parking in any reserved or assigned parking spaces of Tenant.  Tenant
         shall, if requested by Landlord, furnish to Landlord a complete list
         of the license plate numbers of all vehicles operated by Tenant and
         Tenant's employees and agents.  Landlord shall not be liable for any
         damage of any nature whatsoever to, or any theft of, vehicles, or
         contents therein, in or about such parking facility.  If, for any
         reason, Landlord fails or is unable to provide, or Tenant is not
         permitted to use, all or any portion of the parking spaces to which
         Tenant is entitled hereunder, then Tenant's obligation to pay for such
         spaces shall be abated for so long as Tenant does not have the use
         thereof; this abatement shall be in full settlement of all claims that
         Tenant might otherwise have against Landlord because of Landlord's
         failure or inability to provide Tenant with such parking spaces.

                 (c)      Rules and Regulations.  To establish and amend from
         time to time rules and regulations governing all tenants' use and
         occupancy of the Building, provided that in the event of a conflict
         between those rules and this Lease, this Lease shall control.(110)
         The rules and regulations now enforced by Landlord are(111).

                 (d)      Food Preparation.  To prohibit the preparation of
         food within the Premises for commercial purposes or the placing of
         vending or dispensing machines of any kind in or about the Premises if
         such vending or dispensing machines are available to the general
         public.

                 (e)      Signs.  (112)prohibit all signs, posters,
         advertisements, or notices from being painted or affixed on any of the
         windows, or doors, or any other part of the Building, except of such
         color, size, and style, and in such places as shall be first approved
         in writing by Landlord(113).





__________________________________

     110 Such  rules  and regulations  will  be uniformly  applied to and
enforced  against  all tenants  in the Building.

     111 attached hereto as Exhibit E, and are subject to change from time to
time

     112 Except as otherwise provided in this Lease, to

     113 , which approval shall not be unreasonably  withheld as long as any
such signs, posters,  advertisements or notices are consistent with the
operation and appearance of the Building as a Class A office building

                                      -36-
<PAGE>   37
                 (f)      Security Measures.  To take all such reasonable
         measures as Landlord may deem advisable for the security of the
         Building and its occupants(114).  Landlord, however, shall have no
         liability to Tenant or its employees, agents, invitees or licensees
         for loss of property or personal injury except to the extent caused by
         Landlord's gross negligence or willful misconduct.  Tenant shall
         cooperate fully in Landlord's efforts to maintain security in the
         Building and shall follow all regulations promulgated by Landlord with
         respect thereto.

                 (g)      Right To Relocate Tenant. (115)any time after the
         execution of this Lease and on thirty (30) days prior written notice,
         Landlord may substitute for the Premises other premises in the
         Building (the "New Premises"), in which event the New Premises shall
         be deemed to be the Premises for all purposes hereunder, provided: (i)
         the New Premises shall be similar in area, finish and appropriateness
         for the Permitted Use; (ii) the Basic Rental and other rentals payable
         under this Lease shall remain the same; and (iii) reasonable out-of-
         pocket costs in connection with relocation to the New Premises shall
         be reimbursed by Landlord after receipt of third party invoices
         therefor.

         18.     HAZARDOUS MATERIAL; INDEMNITY.

                 (a)      Indemnity.  Tenant shall not cause or permit any
         Hazardous Material (as hereinafter defined) to be brought upon, kept
         or used in or about the Premises or the Project by Tenant or its
         agents, employees, contractors or invitees without the prior written
         consent of Landlord (which Landlord shall not unreasonably withhold as
         long as Tenant demonstrates to Landlord's reasonable satisfaction that
         such Hazardous Material is necessary or useful to Tenant's business
         and will be used, kept and stored in a manner that complies with all
         laws regulating any such Hazardous Material so brought upon or used or
         kept in or about the Premises or the Project).(116)  If Tenant
         breaches the obligations stated in the preceding sentence, or if the
         presence of Hazardous Material on the Premises or the Project caused
         or permitted by Tenant results in contamination of the Premises or the
         Project, or if contamination of the Premises or the Project by
         Hazardous Material otherwise occurs for which Tenant is legally liable
         to Landlord for damage resulting therefrom, then Tenant shall
         indemnify, defend and hold Landlord harmless





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     114 ;  provided,  that such  measures shall  be  commensurate with the
security  provided for  buildings of similar size and quality in the Dallas,
Texas area

     115 With respect  to the portion  of the Premises  located on multiple 
tenant floors of the  Building only, excluding the first floor of the Building,
at

     116 Notwithstanding the foregoing, Tenant may, without Landlord's prior
consent, but in compliance with all Applicable Laws, use any ordinary and
customary Hazardous Material reasonably required to be used by Tenant in the
normal course of Tenant's business permitted on the Premises, so long as such
Hazardous Material is used, kept and stored in a manner that complies with all
laws regulating any such Hazardous Material.

                                      -37-
<PAGE>   38
         from any and all claims, judgments, damages, penalties, fines, costs,
         liabilities or losses, including, without limitation, diminution in
         value of the Premises, damages, penalties, fines, costs, liabilities
         or losses (including, without limitation, restriction on use of
         rentable or usable space or of any amenity of the Premises or the
         Project, damages arising from any adverse impact on marketing of
         space, and sums paid in settlement of claims, attorneys' fees,
         consultant fees and expert fees) which arise during or after the Lease
         Term as a result of such contamination.  This indemnification of
         Landlord by Tenant includes, without limitation, costs incurred in
         connection with any investigation of site conditions or any clean up,
         remedial, removal or restoration work required by any federal, state
         or local governmental agency or political subdivision because of
         Hazardous Material(117) present in the soil or ground water on or under
         the Premises or the Project.  Without limiting the foregoing, if the
         presence of any Hazardous Material on the Premises or the Project
         caused or permitted by Tenant results in any contamination of the
         Premises or the Project, Tenant shall promptly take all actions at its
         sole expense as are necessary to return the Premises and the Project
         to the condition existing prior to the introduction of any such
         Hazardous Material to the Premises or the Project; provided that
         Landlord's approval of such actions shall first be obtained, which
         approval shall not be unreasonably withheld so long as such actions
         would not potentially have any material adverse long-term or
         short-term effect on the Premises or the Project.  The indemnification
         of Landlord by Tenant contained in this Paragraph 18 shall survive the
         expiration or earlier termination of this Lease.

                 (b)      Definition.  As used herein, the term "Hazardous
         Material" means any hazardous or toxic substance, material or waste
         which is or becomes regulated by any local governmental authority, the
         State of Texas or the United States Government, including, but not
         limited to, any material or substance that is (i) petroleum, (ii)
         asbestos, (iii) designated as a "hazardous substance" pursuant to
         Section 311 of the Water Pollution Control Act (33 U.S.C. Section
         1321), (iv) defined as a "hazardous waste" pursuant to Section 1004 of
         the Resource Conservation and Recovery Act, 42 U.S.C. Section  6901,
         (v) defined as a "hazardous substance" pursuant to Section 101 of the
         Comprehensive Environmental Response, Compensation and Liability Act,
         42 U.S.C.  Section  9601, or (vi) defined as a "regulated substance"
         pursuant to Subchapter IX, Solid Waste Disposal Act, 42 U.S.C. Section
         6991.

                 (118)





__________________________________

     117 caused or permitted by Tenant to be

     118 Landlord has provided Tenant with a copy of the Environmental Site
Assessment for the Project prepared by Law Engineering and Environmental
Services and dated February 1996 (the "Environmental Report").  Except as
otherwise provided in the Environmental Report, Landlord has no actual knowledge
of the presence of any Hazardous Material in, on, under or about the Premises.

                                      -38-
<PAGE>   39
         19.     MISCELLANEOUS.

                 (a)      Time Is of the Essence.  The time of the performance
         of all of the covenants, conditions and agreements of this Lease is of
         the essence.

                 (b)      Force Majeure.  If either Landlord or Tenant is
         prevented or hindered from timely satisfying any provisions set forth
         herein because of a shortage of or inability to obtain materials or
         equipment, strikes or other labor difficulties, governmental
         restrictions, casualties or any other cause beyond such party's
         reasonable control, such party shall be permitted an extension of time
         of performance by the number of days during which such performance was
         prevented or hindered; provided, however, that this paragraph shall
         not apply to the payment of rent or other monies by Landlord or
         Tenant(119), nor shall the provisions of this paragraph postpone the
         date that rent is payable pursuant to this Lease, except as expressly
         provided to the contrary in the Construction Agreement (if any)
         entered into pursuant to Paragraph 4.

                 (c)      No Personal Liability of Landlord.  If Landlord shall
         fail to perform any covenant, term or condition of this Lease and, as
         a consequence, if Tenant shall recover a money judgment against
         Landlord, such judgment shall be satisfied only out of the proceeds
         received at a judicial sale upon execution and levy against the right,
         title and interest of Landlord in the Building and in the rents or
         other income from the Building receivable by Landlord, and neither
         Landlord nor Landlord's affiliated companies nor their respective
         owners, partners, venturers, shareholders, directors or officers shall
         have any personal, corporate or other liability hereunder.(120)





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     119 (except as otherwise set forth in this Lease)

     120 If Tenant recovers a final, non-appealable money judgment against
Landlord for Landlord's default of its obligations hereunder or otherwise, such
judgment shall be satisfied from (i) the proceeds of sale received upon
execution of such judgment and levy thereon against the right, title and
interest of Landlord in the Project (or any portion thereof), (ii) rent or other
income from the Project received and/or receivable by Landlord, (iii) a credit
against future rent and other charges as they become payable under this Lease,
and/or (iv) the consideration received by Landlord from the sale or other
disposition of all or any part of Landlord's right, title or interest in the
Project or any portion thereof; provided further, that in the event of
Landlord's failure to perform any covenant or obligation of Landlord under
either Paragraph 11 or Paragraph 12 of this Lease, following damage to or
destruction of or a taking of all or any part of the Project, any final,
non-appealable judgment recovered by Tenant as a consequence thereof may also be
satisfied out of the insurance proceeds or condemnation award, as the case may
be, paid and/or payable to Landlord as a result of such damage, destruction or
taking.  The provisions of this paragraph shall not be deemed to deny Tenant, or
to lessen Tenant's right to obtain, injunctive relief or specific performance of
Landlord's covenants under this Lease or to avail itself of any other right or
remedy (not involving the personal liability of Landlord) which may be afforded
to Tenant by law or under the terms of this Lease by reason of Landlord's
failure to perform its obligations under this Lease.

                                      -39-
<PAGE>   40
                 (d)      Quiet Enjoyment.  Landlord hereby covenants and
         agrees that if Tenant shall perform all of the covenants and
         agreements herein stipulated to be performed on Tenant's part, Tenant
         shall at all times during the continuance hereof have peaceable and
         quiet enjoyment and possession of the Premises without hindrance from
         Landlord or any person or persons lawfully claiming the Premises by or
         through Landlord, subject, however, to the terms of this Lease and to
         all mortgages, ground leases, deeds of trust, leases and agreements to
         which this Lease is subordinate.

                 (e)      Entire Agreement and Amendments.  This Lease is the
         only agreement between the parties hereto and their representatives
         and agents.  There are no representations or warranties between the
         parties other than the representations and warranties contained in
         this document.  No agreement shall be effective to change, modify or
         terminate this Lease in whole or in part unless such agreement is in
         writing and duly signed by the party against whom enforcement of such
         change, modification or termination is sought.

                 (f)      Interpretation.  The necessary grammatical changes
         required to make the provisions of this Lease apply in the plural
         sense where there is more than one Tenant and to either corporations,
         associations, partnerships or individuals, male or female, shall in
         all instances be assumed as though in each case fully expressed.  The
         laws of the State of Texas shall govern the validity, performance and
         enforcement of this Lease.  All obligations hereunder are performable
         in Dallas County, Texas.  If this Lease is executed by more than one
         person or entity as "Tenant",  each such person or entity executing
         this Lease as Tenant shall be jointly and severally bound and liable
         hereunder.

                 (g)      Severability.  No provision of this Lease shall be
         construed or interpreted in any manner which would render such
         provision invalid.  If any provision of this Lease is held to be
         invalid, such invalid provision shall be deemed to be severable from
         and shall not affect the validity of the remainder of this Lease.

                 (h)      Terms Binding.  Subject to the limitations on
         subletting and assignment set forth in this Lease, all covenants,
         promises, conditions, representations and agreements herein contained
         shall be binding upon and apply and inure to the benefit of the
         parties hereto and their respective heirs, executors, administrators,
         successors and assigns.

                 (i)      Estoppel Certificates.  Within(121) days after
         request by Landlord, Tenant agrees to execute and deliver to Landlord
         estoppel or offset letters as required by Landlord or by Landlord's
         lenders.  The letters shall certify the date of this Lease and any
         amendments, that Landlord is not in default of any of the terms and
         provisions of





__________________________________

     121 ten (10) business

                                      -40-
<PAGE>   41
         this Lease or specifying the provisions as to which Landlord is in
         default if Landlord shall be in default, that Landlord has performed
         all inducements required of Landlord in connection with this Lease,
         including any construction obligations, specifying any inducements
         which have not been fulfilled by Landlord, the date to which rent has
         been paid, and any other matters which Landlord or its lenders may
         reasonably require.  Tenant's failure to deliver such letters to
         Landlord within said(122) day period will be conclusive evidence of
         the matters set forth therein.  Tenant further agrees to furnish to
         Landlord from time to time when requested by Landlord a letter of
         acceptance in conformity with any requirements made by any existing or
         proposed lenders.

                 (j)      Late Payment Charge and Interest Payable.  Landlord
         may impose a late payment charge equal to five percent (5%) of any
         amount due if not paid within five (5) days from the date required to
         be paid hereunder.  In addition, any payment due under this Lease not
         paid within ten (10) days after the date herein specified to be paid
         shall bear interest from the date such payment is due to the date of
         actual payment at the rate of(123) per annum or the highest lawful
         rate of interest permitted by Texas or federal law, whichever rate of
         interest is lower.

                 (k)      Security Deposit.  Tenant shall deposit with Landlord
         the amount shown in Paragraph 1(e) above as a Security Deposit(124).
         Landlord shall hold Tenant's Security Deposit without interest, and
         the same shall not be considered prepaid rent or a measure of
         Landlord's damages in case of default by Tenant.  The remaining
         balance of the Security Deposit (after application of any part thereof
         in accordance with Paragraph 13(b) or for necessary repairs to the
         Premises) shall be refundable to Tenant within thirty (30) days after
         the expiration or earlier termination of this Lease.

                 (l)      Access to Premises.  Tenant agrees that Landlord and
         its agents may enter the Premises for the purpose of inspecting and
         making such repairs (structural or otherwise), additions,
         improvements, changes or alterations to the Premises or the Building
         as may be permitted or required under this Lease or as Landlord may
         elect, and to exhibit the same to prospective purchasers, mortgagees
         or(125) tenants.  In the event of any such repairs, additions,
         improvements, changes or alterations, Tenant shall





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     122 ten (10) business

     123 fourteen percent (14%)

     124 in three (3) separate installments as follows: (i) $47,725.00 within
five (5) business days after execution of this Lease, (ii) $95,450.00 on the
Commencement Date of this Lease (as such term is defined in Paragraph 3
contained herein), and (iii) $47,725.00 on or before December 1, 1997

     125 , during the last year of the Lease Term, to prospective

                                      -41-
<PAGE>   42
         cooperate with Landlord to facilitate Landlord's efforts.  Landlord's
         entries in the Premises shall be preceded by reasonable notice (except
         in the case of an emergency) and shall not unreasonably interfere with
         Tenant's use and occupancy of the Premises for the Permitted Use.

                 (m)      Notices.  Notices hereunder must be hand-delivered or
         sent by(126) nationally recognized overnight courier or by certified
         mail, return receipt requested, postage prepaid, addressed, if to
         Landlord, at Suite 110, 3333 Lee Parkway, Dallas, Texas  75219,
         Attention: Property Manager, with a copy to Crescent Real Estate
         Equities Limited Partnership, 777 Main Street, Suite 2100, Fort Worth,
         Texas 76102, Attention: James S.  Wassel, and if to Tenant, at the
         address specified for Tenant in Paragraph 1(a) above prior to the
         Commencement Date and to the Premises thereafter, or to such other
         address as may be specified by written notice actually received by the
         other party.  Notice shall be deemed given upon tender of delivery (in
         the case of a hand- delivered notice) or upon posting of same with the
         overnight courier service or in an official depository of the United
         States Postal Service (in the case of a certified or registered
         letter), provided that no notice of either party's change of address
         shall be effective until fifteen (15) days after the addressee's
         actual receipt thereof.

                 (n)      Acceptance of Premises and Building by Tenant.
         LANDLORD HEREBY DISCLAIMS ANY EXPRESS OR IMPLIED REPRESENTATION OR
         WARRANTY THAT THE PREMISES ARE SUITABLE FOR TENANT'S INTENDED PURPOSE
         OR USE. THE TAKING OF POSSESSION BY TENANT SHALL BE CONCLUSIVE
         EVIDENCE THAT TENANT:

                         (I)  ACCEPTS THE PREMISES AS SUITABLE FOR THE PURPOSES
                 FOR WHICH THEY WERE LEASED;

                          (II)  ACCEPTS THE BUILDING AND EVERY PART AND
                 APPURTENANCE THEREOF(127) AS BEING IN GOOD AND SATISFACTORY
                 CONDITION; AND

                          (III)  WAIVES ANY DEFECTS IN THE PREMISES AND ITS
                 APPURTENANCES EXISTING NOW OR IN THE FUTURE (128), EXCEPT THAT
                 TENANT'S TAKING OF POSSESSION SHALL NOT BE DEEMED TO WAIVE
                 LANDLORD'S COMPLETION OF MINOR FINISH WORK ITEMS





__________________________________

     126 facsimile (with electronic confirmation) or by

     127 (EXCLUDING LATENT DEFECTS)

     128 (EXCLUDING LATENT DEFECTS)

                                      -42-
<PAGE>   43
                 THAT DO NOT INTERFERE WITH TENANT'S OCCUPANCY OF THE PREMISES.

         TENANT ACKNOWLEDGES THE DISCLAIMER BY LANDLORD SET FORTH HEREIN AND
         WAIVES ALL CLAIMS BASED ON ANY IMPLIED WARRANTY OF SUITABILITY.
         FURTHERMORE, TENANT CONFIRMS THAT ITS OBLIGATIONS TO PAY BASIC RENTAL,
         ADDITIONAL RENTAL AND OTHER AMOUNTS OF MONEY DUE TO LANDLORD HEREUNDER
         ARE NOT DEPENDENT OF THE CONDITION OF THE PREMISES OR THE BUILDING,
         THE COMPLETION OF ANY MINOR FINISH WORK ITEMS OR THE PERFORMANCE BY
         LANDLORD OF ITS OBLIGATIONS HEREUNDER.  TENANT SHALL CONTINUE TO PAY
         BASIC RENTAL, ADDITIONAL RENTAL AND OTHER AMOUNTS OF MONEY DUE TO
         LANDLORD HEREUNDER, WITHOUT ABATEMENT, SETOFF OR DEDUCTION,
         NOTWITHSTANDING ANY BREACH OR ALLEGED BREACH BY LANDLORD OF ITS
         OBLIGATIONS HEREUNDER.

                 (o)      Building Name.  (129)

                 (p)      Landlord's Lien.  (130)





__________________________________

     129 Landlord agrees that, so long as Tenant occupies at least 120,000
square feet of Rentable Area in the Building, Tenant shall have the right to
designate the name of the Building.  Tenant agrees that the name selected by
Tenant shall be subject to Landlord's reasonable approval, and shall not be
changed thereafter.  Tenant further agrees that Landlord shall not be required
to use the name on stationary, cards, and other printed material used by the
management of the Building.

     130 Landlord hereby agrees that no equipment, furnishings, furniture,
supplies or other personal property of any kind (other than fixtures and items
which Landlord and Tenant have agreed in writing will remain the property of
Landlord upon the expiration or earlier termination of this Lease) which are
placed upon or permitted to be placed upon the Premises by Tenant, or by any of
Tenant's employees, agents, representatives, subtenants, successors or assigns,
during the term of this Lease or any renewal thereof, shall be subject to or
liable for levy or distress or any legal process whatsoever for the collection
of rent, additional rent or other charges payable hereunder by Tenant.  Landlord
thus hereby waives, releases and negates any and all contractual liens and
security interests, constitutional liens and security interests, statutory liens
and security interests and/or any and all other liens and security interests,
arising by operation of law or otherwise, to which Landlord might now or
hereafter be entitled upon all equipment, furnishings, furniture, supplies,
trade fixtures or other personal property which Tenant now or hereafter places
(or causes or permits to be placed) in or upon the Premises.

                                      -43-
<PAGE>   44
                 (q)      Authority To Sign Lease.  If Tenant is a corporation
         or a partnership (general or limited), each person(s) signing this
         Lease as an officer or partner of Tenant represents to Landlord that
         such person(s) is authorized to execute this Lease without the
         necessity of obtaining any other signature of any other officer or
         partner, that the execution of this Lease has been authorized by the
         board of directors of the corporation or by the partners of the
         partnership, as the case may be, and that this Lease is fully binding
         on Tenant.  Landlord reserves the right to request evidence of the
         approval of





                                      -44-
<PAGE>   45
         this Lease and authorization of Tenant's signatories to bind Tenant,
         which evidence shall be satisfactory in form and content to Landlord
         and its counsel.

                 (r)      Attorneys' Fees.  In the event either party is in
         default beyond any applicable grace or notice period in the
         performance of any of the terms of this Lease and the other party
         employs an attorney in connection therewith, the nonprevailing party
         agrees to pay the prevailing party's reasonable attorneys' fees.

                 (s)      Execution of Lease.  The submission of this Lease for
         examination does not constitute a reservation of or option for the
         Premises or any other space within the Building and shall vest no
         right in either party.  This Lease shall become effective only after
         the full execution and delivery hereof by all of the parties hereto
         and upon the approval by the holder of any mortgage encumbering the
         Project.

                 (t)      No Attornment.  All checks tendered to Landlord as
         and for the Basic Rental and/or Additional Rental required hereunder
         shall be deemed payments for the account of Tenant.  Acceptance by
         Landlord of Basic Rental and/or Additional Rental from anyone other
         than Tenant shall not be deemed to operate as an attornment to
         Landlord by the payor of such Basic Rental and/or Additional Rental or
         as a consent by Landlord to an assignment of this Lease or subletting
         by Tenant of the Premises to such payor, or as a modification of any
         of the provisions of this Lease.

                 (u)      Applicable Laws.  As used herein, the term
         "Applicable Laws" shall mean all laws, statutes, ordinances,
         regulations, guidelines or requirements now in force or hereafter
         enacted and the requirements of any governmental authority having
         jurisdiction over the Building, board of fire underwriters, utility
         company serving the Building or other similar body now or hereafter
         constituted, relating to or affecting the condition, use or occupancy
         of the Premises, including without limitation, Title III of The
         Americans with Disabilities Act of 1990, all regulations issued
         thereunder, and the Accessibility Guidelines for Buildings and
         Facilities issued pursuant thereto, and the Texas Architectural
         Barriers Act, as the same are in effect on the date of this Lease and
         as hereafter amended.

                 (v)      Arms-Length Transaction.  This Lease has been entered
         into by the undersigned after arms-length negotiation, with each party
         acknowledging that it and its counsel, if it so chooses, have had an
         opportunity to review this Lease, and therefore, the parties agree
         that this Lease shall not be construed against Landlord on the ground
         that Landlord's representatives prepared this Lease.

                 (w)      Waiver.  No covenant, term or condition or the breach
         thereof will be deemed waived, except by written consent of the party
         against whom the waiver is claimed and any waiver of the breach of any
         covenant, term or condition will not be deemed to be a waiver of any
         preceding or succeeding breach of the same or any other





                                      -45-
<PAGE>   46
         covenant, term or condition.  Acceptance by Landlord of any
         performance by Tenant after the time the same was due will not
         constitute a waiver by Landlord of the breach or default of any
         covenant, term or condition unless otherwise expressly agreed to by
         Landlord in writing.

                 (x)      Computation of Rentable Area.

                          (1)     Single Tenant Floor.  With respect to a
         single tenant floor, "Rentable Area" will mean the sum of (i) the
         floor area (in square feet) bounded by the inside surfaces of the
         exterior glass walls of the Building, excluding standard openings in
         the floor slab used, for example, for Building stairs, elevator and
         other shafts and vertical ducts (collectively, the "Excluded Spaces"),
         and (ii) an allocation of the floor area of Common Areas and Service
         Areas located in or serving the Building.

                          (2)     Multiple Tenant Floor.  With respect to a
         multiple tenant floor, "Rentable Area" will mean the sum of (i) the
         floor area (in square feet) bounded by the inside surfaces of the
         exterior glass walls, the outside surfaces of partitions separating
         the Premises from corridors and other Common Areas and Service Areas,
         and the center line of partitions separating the Premises from
         adjoining leasable spaces, less any Excluded Spaces located within
         such boundaries, and (ii) an allocation of the floor area of the
         Common Areas and Service Areas on such floor, and (iii) an allocation
         of the floor area of Common Areas and Service Areas located in or
         serving the Building.

                          (3)     Columns and Non-Standard Openings.  No
         deductions will be made in either Paragraph 19(x)(1) or Paragraph
         19(x)(2) for (i) columns and projections necessary to the structural
         support of the Building or (ii) for openings in the floor slab which
         were made at the request of Tenant or to accommodate items installed
         at the request of Tenant.

                 (y)      Exhibits and Riders.  The following exhibits and
         riders are attached hereto, incorporated herein and made a part of
         this Lease for all purposes:

<TABLE>
                          <S>                               <C>
                          Exhibit A-1:                      Floor Plan of Premises
                          Exhibit A-2:                      Property Description
                          Exhibit B:                        Certificate of Acceptance of Premises
                          Exhibit C:                        Construction Agreement
                          Exhibit D:                        Building Standard Janitorial Services
                          Exhibit E:                        Building Rules and Regulations
                          Exhibit F:                        Rooftop License Agreement
                          Rider No. 101:                    Leasing Rights and Obligations
                          Rider No. 201:                    Option to Expand
                          Exhibit 201-A:                    Columbia Space
                          Rider No. 301:                    Right of First Refusal
</TABLE>





                                      -46-
<PAGE>   47
<TABLE>
                          <S>                               <C>
                          Exhibit 301-A:                    Right of First Refusal Space
                          Rider No. 401:                    Option to Extend
                          Rider No. 501:                    Termination Option
</TABLE>

                 (z)      Counterparts.  This Lease may be executed in several
         counterparts, each of which will be deemed an original, and all of
         which will constitute but one and the same instrument.

                 (131)





__________________________________

     131         (aa)    Club Memberships.  Landlord agrees to pay, out of the
Basic Rental payable for the first month of the Lease Term, either directly to
Tenant or, at the request of Tenant, on behalf of Tenant, the initiation fees in
connection with a total of eighteen (18) memberships to either The Crescent Club
or The Spa at The Crescent, which memberships will be activated on the
Commencement Date (or as soon thereafter as is practicable). The issuance of
such memberships shall be subject to the prior approval of the applicable of The
Crescent Club and The Spa at The Crescent.  Monthly dues and all other expenses
incurred by Tenant or any other person in connection with the use of such
memberships shall be solely the responsibility of Tenant.

                 (bb)     Signage.  Landlord agrees that, during the term of
this Lease, Tenant shall have the right to place exterior signage reflecting
Tenant's name on the upper portion of two (2) opposite sides of the Building
and the non-exclusive right to place Tenant's name on the monument sign in
front of the Building (collectively, the "Signage").  The Signage shall be
installed and maintained at Tenant's sole cost and expense throughout the term
of this Lease; provided, however that, at Tenant's option, the cost of
installing the Signage may be included in the cost of the Finish Work and may
be paid out of the Finish Allowance (as such terms are defined in the
Construction Agreement attached hereto as Exhibit C) to the extent sufficient
funds are available for such purpose.  The location, size, material and design
of the Signage shall be subject to the prior written approval of Landlord, and
Tenant shall be responsible for compliance with any laws, rules, regulations,
ordinances, building codes, restrictive covenants, or architectural guidelines
applicable to the Project, as the same may be amended or modified from time to
time.  Upon the expiration or earlier termination of this Lease, Tenant shall
remove the Signage, at Tenant's sole cost and expense, and restore the areas of
the Project to which the Signage was affixed to their condition prior to the
installation of the Signage.

                 (cc)     Rooftop Access.  Tenant may install communication
equipment and related wiring on the roof of the Building pursuant to the terms
and conditions of the Rooftop License Agreement attached to this Lease as
Exhibit F.

                 (dd)     Broker.  Landlord and Tenant each warrant and
represent to the other that neither has dealt with any real estate broker,
agent or finder in connection with this transaction other than The Staubach
Company ("Staubach"), which is acting as Tenant's agent in connection herewith;
and Landlord and Tenant agree to protect, defend, indemnify and hold harmless
the other from and against any and all liabilities, costs, causes of action,
damages and expenses, including without limitation, attorneys' fees, for any
claims made by any real estate broker, agent or finder with respect to this
transaction other than claims of Staubach, which shall be compensated by
Landlord pursuant to a separate agreement.

                 (ee)     Lobby Improvements.  Landlord will construct certain
improvements to the lobby of the Building (the "Lobby Improvements").  Prior to
the commencement of construction of the Lobby Improvements, Landlord shall
deliver to Tenant plans and specifications for the Lobby Improvements for
Tenant's review and approval, which approval shall not be unreasonably withheld
or delayed.  Landlord agrees that the total cost of the Lobby Improvements
shall be at least $40,000.00, and that Landlord shall commence construction of
the Lobby Improvements during construction of the First Expansion Space Finish
Work (as such term is defined in the Construction Agreement), and Landlord
shall complete construction of the Lobby Improvements no later than the date of
substantial completion of the First Expansion Space Finish Work.

                                      -47-
<PAGE>   48
                 [Remainder of page intentionally left blank.]





                                      -48-
<PAGE>   49
         IN WITNESS WHEREOF, the parties hereto have executed and delivered
this Lease as of the day and year first above written.


                      LANDLORD:
                      -------- 

                      CRESCENT REAL ESTATE EQUITIES LIMITED
                      PARTNERSHIP, a Delaware limited partnership

                      By:      Crescent Real Estate Equities, Ltd.,
                               a Delaware corporation, its general partner


                               By:     /s/ JAMES S. WASSEL
                                       ----------------------------------------
                                       Name: James S. Wassel
                                       Title: Senior Vice President


                      TENANT:
                      ------ 

                      PAGEMART WIRELESS, INC.,
                      a Delaware corporation



                      By:      /s/ JOHN D. BELETIC
                               ------------------------------------------------
                               Name:   John D. Beletic
                               Title:  President, CEO                           





                                      -49-
<PAGE>   50
                                  EXHIBIT A-1

                             FLOOR PLAN OF PREMISES

                                [To be attached]
<PAGE>   51
                                  EXHIBIT A-2

                              PROPERTY DESCRIPTION

BEING all of Lot 8A, Block Z/1039 of Bank of Dallas Addition, an addition to
the City of Dallas as recorded in Volume 82054, Page 2955, Deed Records, Dallas
County, Texas and being more particularly described as follows:

BEGINNING at an "x" set for corner in the Easterly line of Welborn Street (a
60' R.O.W.), said point being the Northwest corner of Block Z/1039;

THENCE South 45 degrees 00 minutes East, along the Southerly line of Rawlins
Street, 400 feet to an "x" set for corner, said point being the Northeast
corner of Block Z/1039;

THENCE South 45 degrees 00 minutes West, along the Westerly R.O.W. line of Lee
Parkway (a 60' R.O.W.), 153 feet to an "x" set for corner;

THENCE North 45 degrees 00 minutes West, along the North side of a 15 foot
alley, 400 feet to an "x" set for corner in the Easterly R.O.W. line of Welborn
Street;

THENCE North 45 degrees 00 minutes East, along said Easterly R.O.W. line of
Welborn Street, 153 feet to the POINT OF BEGINNING and containing 61,200 square
feet of land, more or less.
<PAGE>   52
                                   EXHIBIT B

                     CERTIFICATE OF ACCEPTANCE OF PREMISES

         Re:     Office Lease for space in 3333 Lee Parkway, dated the _____
day of ______________, 1996, between Crescent Real Estate Equities Limited
Partnership ("Landlord"), and PageMart Wireless, Inc. ("Tenant").

         Landlord and Tenant hereby agree that:

         1.      Except for those items shown on the attached "punch list", if
any, Landlord has fully completed any construction work required under the
terms of the Lease.

         2.      The Premises are tenantable, the Landlord has no further
obligation for construction (except as specified above), and Tenant
acknowledges that both the Building and the Premises (excluding any latent
defects) are satisfactory in all respects.

         3.      The Commencement Date of the Lease is the _____ day of
                 ________________, 19__.

         4.      The Expiration Date of the Lease is to be the _____ day of
                            _______________, 19___.

         All other terms and conditions of the Lease are hereby ratified and
acknowledged to be unchanged.

         EXECUTED this _____ day of ______________________, 1996.



TENANT:                                LANDLORD:
------                                 -------- 
                                     
PAGEMART WIRELESS, INC.                CRESCENT REAL ESTATE EQUITIES
                                       LIMITED PARTNERSHIP
                                     
By:                                    By:  Crescent Real Estate Equities, Ltd.,
    --------------------------              its General Partner
    Name:                                                      
           -------------------                                    
    Title:                           
           -------------------       
                                     
                                       By:        
                                            -----------------------------------
                                            Name:       
                                                  -----------------------------
                                            Title:      
                                                  -----------------------------
<PAGE>   53
                                   EXHIBIT C

                             CONSTRUCTION AGREEMENT

         This Construction Agreement is executed by and between CRESCENT REAL
ESTATE EQUITIES LIMITED PARTNERSHIP ("Landlord") and PAGEMART WIRELESS, INC.
("Tenant") in connection with that certain Office Lease (the "Lease") executed
by the parties on even date herewith (the "Effective Date") relating to the
lease by Landlord to Tenant of certain premises in the building commonly known
as "3333 Lee Parkway", and located at 3333 Lee Parkway, Dallas, Texas.  All
defined terms used herein, unless otherwise defined herein, shall have the same
meanings given to such terms in the Lease.

         Landlord shall construct, or cause to be constructed, leasehold
improvements in and upon the Premises in up to a total of three (3) separate
phases as Landlord prepares the Initial Space, the First Expansion Space and
the Second Expansion Space for occupancy by Tenant.  Landlord agrees that
Tenant may require, at Tenant's option, that Landlord construct the leasehold
improvements for the First Expansion Space and the Second Expansion Space
simultaneously.  Landlord's construction of all phases of the leasehold
improvements shall be governed by the terms and conditions of this Construction
Agreement, and all defined terms used herein shall have their respective
meanings in connection with the construction of the leasehold improvements for
the Initial Space, the First Expansion Space, and the Second Expansion Space.
If Tenant elects to have the leasehold improvements for the First Expansion
Space and Second Expansion Space constructed simultaneously, then the term
"First Expansion Space" wherever used in this Lease shall be deemed to include
the Second Expansion Space, and all terms and provisions of this Lease
referring to the term "Second Expansion Space" shall be null, void, and of no
further force or effect.

         (a)     Construction Costs.  Landlord shall construct, or cause to be
constructed, leasehold improvements (the "Finish Work"), in a good and
workmanlike manner in and upon the applicable space, in accordance with the
Final Working Drawings (hereinafter defined).  Landlord shall provide Tenant
with an allowance to be applied towards the cost of constructing the Finish
Work in an amount not to exceed $15.00 per rentable square foot in the
applicable space (the "Finish Allowance").  The cost of all space planning and
construction drawings shall be included in the cost of the Finish Work and may
be paid out of the Finish Allowance, to the extent sufficient funds are
available for such purpose.  In the event that the total cost of the Finish
Work exceeds the Finish Allowance, Tenant may elect to (i) pay such excess
amount to Landlord promptly upon demand prior to Landlord's commencing
construction, or (ii) with respect to a portion of such excess, not to exceed
an amount equal to $8.00 per rentable square foot in the applicable space (the
"Amortizable Amount"), increase the amount of monthly payments of Basic Rental
due under the Lease by an amount equal to the amount of the monthly installment
payment which would be required to fully amortize a loan of a principal amount
equal to the Amortizable Amount bearing interest at twelve and one-half percent
(12.5%) per annum, and having a loan term equal to the initial term of the
Lease with respect to the Initial
<PAGE>   54
Space, and equal to the remainder of the initial term of the Lease with respect
to the First Expansion Space and the Second Expansion Space.  Change orders
requested by Tenant and approved by Landlord after construction has commenced
and which increase the cost of construction over the amount of the Finish
Allowance shall be paid by Tenant to Landlord promptly upon demand.  All
installations and improvements now or hereafter placed in the Premises other
than Building Standard (as defined in the Lease) improvements shall be for
Tenant's account and at Tenant's cost (and Tenant shall pay ad valorem taxes
and increased insurance thereon or attributable thereto), which cost shall be
payable by Tenant to Landlord upon demand as additional rent.  Tenant further
agrees to pay Landlord a fee of three percent (3%) of the contract price for
the Finish Work (the "Construction Management Fee") as compensation for
Landlord's supervision of the construction and installation of the Finish Work
on the commencement of construction thereof.  Landlord and Tenant agree that
the Construction Management Fee may be paid out of the Finish Allowance to the
extent funds are available for such purpose.  Tenant agrees that in the event
of default of payment thereof, Landlord (in addition to all other remedies)
shall have the same rights as in the event of default of payment of rent under
the Lease.

         (b)     Preparation of Plans.  Tenant shall deliver to Landlord
preliminary construction drawings and space plans (the "Preliminary Plans") for
the Finish Work no later than the applicable Preliminary Plans Date
(hereinafter defined).  Landlord will review the Preliminary Plans and notify
Tenant of Landlord's reasonable approval or disapproval thereof (and any such
notice of disapproval shall state the reasons for Landlord's disapproval)
within five (5) business days after receipt of the Preliminary Plans.  Tenant
shall then revise the Preliminary Plans and resubmit them to Landlord for
Landlord's approval or disapproval within five (5) business days of Tenant's
receipt of Landlord's notice of disapproval.  If Landlord does not notify
Tenant of Landlord's approval or disapproval within the five (5) business day
period, Landlord will be deemed to have approved the Preliminary Plans.  The
Preliminary Plans, as revised and approved by Landlord (or which are deemed to
be approved by Landlord) shall constitute "Final Working Drawings".

         (c)     Construction.  Upon completion of the Final Working Drawings,
Landlord shall select a minimum of three (3) experienced, licensed contractors
(which contractors shall be subject to Tenant's approval) to bid for the
construction of the Finish Work based on the Final Working Drawings.  Landlord
will employ the contractor who submits the lowest qualified and complete bid to
construct the Finish Work and will require in the construction contract that
such contractor construct the Finish Work in a good and workmanlike manner and
in compliance with all Applicable Laws; provided, however, Tenant will be
solely responsible for determining whether or not Tenant is a public
accommodation under The Americans with Disabilities Act and whether or not the
Final Working Drawings comply with such laws and the regulations thereunder.
The parties acknowledge that Landlord is not an architect or engineer, and that
the Finish Work will be designed and performed by independent architects,
engineers and contractors.  Accordingly, Landlord does not guarantee or warrant
that the plans or Final Working Drawings will be free from errors or omissions,
nor that the Finish Work will be free





                                      -2-
<PAGE>   55
from defects, and Landlord will have no liability therefor.  In the event of
such errors, omissions, or defects, Landlord will, at the request of Tenant,
demand performance under any warranties related to the Finish Work and
diligently pursue the enforcement of such warranties, and Landlord will use
reasonable efforts to cooperate in any action Tenant desires to bring against
such parties.

         (d)     Substantial Completion.  For purposes hereof, the Finish Work
shall be deemed to be "substantially complete" when:

                 (i)      all ceilings and lighting in the applicable space are
in and operative;

                 (ii)     all walls and partitions in the applicable space have
been erected with final painting or wall covering complete, and doors and
hardware have been installed;

                 (iii)    all built-in cabinetry, millwork, glass, stairways,
plumbing and bookshelves in the applicable space have been completed and
installed;

                 (iv)     all floor coverings in the applicable space have been
installed;

                 (v)      building elevators, plumbing, HVAC and electrical
systems serving the applicable space have been installed and are in good
working condition; electrical service is adequate for Tenant's lighting
fixtures, office equipment and additional requirements, in keeping with the
approved space plans and Final Working Drawings; and HVAC system has been
balanced;

                 (vi)     all debris has been removed from the applicable
space, and the applicable space cleaned; and

                 (vii)    a certificate of occupancy for the applicable space
has been granted by the City of Dallas, Texas.

         Landlord and Tenant agree that minor "punch-list" type items which do
not impede Tenant's use of the applicable space will not prevent the Finish
Work from being considered "substantially complete".  Prior to the applicable
space being delivered to Tenant, a representative of Landlord and a
representative of Tenant shall walk through the applicable space and jointly
prepare a list (the "Punch List") of minor items which, in the mutual opinion
of Landlord and Tenant, have not been fully completed or require repair (the
"Punch List Items").  Landlord will deliver a copy of the Punch List to Tenant
immediately upon request by Tenant.  Landlord shall diligently cause the
completion of the Punch List Items within a reasonable time after Tenant
commences occupancy of the space, taking reasonable steps to minimize
disruption to Tenant's use and occupancy of the space while the Punch List
Items are being completed.





                                      -3-
<PAGE>   56
         (e)     Delays.

                 (i)      Initial Space.  Subject to the occurrence of a Force
         Majeure Delay or a Tenant Delay (both hereinafter defined), Landlord
         agrees to substantially complete the construction of the Initial Space
         Finish Work by June 1, 1997 (the "Estimated Commencement Date").  In
         the event of a Force Majeure Delay or a Tenant Delay, the Estimated
         Commencement Date shall be extended one (1) day for every day of such
         delay.  If Landlord is delayed in completing such construction by the
         Estimated Commencement Date for any reason other than a Force Majeure
         Delay or a Tenant Delay, then the delay in commencement of Tenant's
         obligation to pay rent under the Lease for that portion of the Initial
         Space which is untenable until ten (10) days after substantial
         completion of the Initial Space Finish Work, shall constitute full
         settlement of all claims that Tenant may have against Landlord based
         on such a delay.  Likewise, if Landlord is delayed in completing such
         construction by the Estimated Commencement Date due to the occurrence
         of a Force Majeure Delay, then the delay in commencement of Tenant's
         obligation to pay rent under the Lease for that portion of the Initial
         Space which is untenable until ten (10) days after substantial
         completion of the Initial Space Finish Work, shall constitute full
         settlement of all claims that Tenant may have against Landlord based
         on such a delay.  However, if Landlord is unable to complete the
         Initial Space Finish Work by the Estimated Commencement Date due to a
         Tenant Delay or due to any other cause related to the acts, neglects,
         failures or omissions of Tenant, Tenant's servants, employees, agents
         or representatives, then Tenant's rental obligations under the Lease
         with respect to the Initial Space shall begin on the date on which
         Landlord would have delivered possession of the Initial Space to
         Tenant absent such Tenant Delay, and such date shall be the Initial
         Space Commencement Date.

                 (ii)     First Expansion Space.  Subject to the occurrence of
         a Force Majeure Delay or a Tenant Delay (both hereinafter defined),
         Landlord agrees to substantially complete the construction of the
         First Expansion Space Finish Work by January 15, 1998 (the "First
         Expansion Space Estimated Commencement Date").  In the event of a
         Force Majeure Delay or a Tenant Delay, the First Expansion Space
         Estimated Commencement Date shall be extended one (1) day for every
         day of such delay.  If Landlord is delayed in completing such
         construction by January 15, 1998, for any reason other than a Force
         Majeure Delay or a Tenant Delay, then (i) Tenant's obligation to pay
         rent under the Lease for that portion of the First Expansion Space
         which is untenable shall be abated until ten (10) days after
         substantial completion of the First Expansion Space Finish Work, and
         (ii) Tenant shall be entitled to an additional rental abatement, which
         shall be applied towards the rent payable for the Initial Space, in an
         amount equal to the difference between (a) the base rental (at the
         holdover rates) payable by Tenant for the portion of Tenant's existing
         premises which Tenant intends to vacate in order to occupy the First
         Expansion Space, and (b) the Basic Rental which would be payable by
         Tenant under this Lease for the First Expansion Space for each day of
         such delay prior to the date of substantial completion of the First
         Expansion Space Finish Work.  The foregoing rental





                                      -4-
<PAGE>   57
         abatements shall constitute full settlement of all claims that Tenant
         may have against Landlord based on such a delay.  Notwithstanding the
         foregoing, if Landlord is delayed in completing such construction by
         January 15, 1998, due to the occurrence of a Force Majeure Delay, then
         the delay in commencement of Tenant's obligation to pay rent under the
         Lease for that portion of the First Expansion Space which is untenable
         until ten (10) days after substantial completion of the First
         Expansion Space Finish Work shall constitute full settlement of all
         claims that Tenant may have against Landlord based on such a delay.
         Furthermore, if Landlord is unable to complete the First Expansion
         Space Finish Work by January 15, 1998, due to a Tenant Delay or due to
         any other cause related to the acts, neglects, failures or omissions
         of Tenant, Tenant's servants, employees, agents or representatives,
         then Tenant's rental obligations under the Lease with respect to the
         First Expansion Space shall begin on the date on which Landlord would
         have delivered possession of the First Expansion Space to Tenant
         absent such Tenant Delay, and such date shall be the First Expansion
         Space Commencement Date.

                 (iii)    Second Expansion Space.  Subject to the occurrence of
         a Force Majeure Delay or a Tenant Delay (both hereinafter defined),
         Landlord agrees to substantially complete the construction of the
         Second Expansion Space Finish Work by May 1, 1998 (the "Second
         Expansion Space Estimated Commencement Date").  In the event of a
         Force Majeure Delay or a Tenant Delay, the Second Expansion Space
         Estimated Commencement Date shall be extended one (1) day for every
         day of such delay.  If Landlord is delayed in completing such
         construction by May 1, 1998, for any reason other than a Force Majeure
         Delay or a Tenant Delay, then (i) Tenant's obligation to pay rent
         under the Lease for that portion of the Second Expansion Space which
         is untenable shall be abated until ten (10) days after substantial
         completion of the Second Expansion Space Finish Work, and (ii) Tenant
         shall be entitled to an additional rental abatement, which shall be
         applied towards the rent payable for the Initial Space and the First
         Expansion Space, in an amount equal to the difference between (a) the
         base rental (at the holdover rates) payable by Tenant for the portion
         of Tenant's existing premises which Tenant intends to vacate in order
         to occupy the Second Expansion Space, and (b) the Basic Rental which
         would be payable by Tenant under this Lease for the Second Expansion
         Space for each day of such delay prior to the date of substantial
         completion of the Second Expansion Space Finish Work.  The foregoing
         rental abatements shall constitute full settlement of all claims that
         Tenant may have against Landlord based on such a delay.
         Notwithstanding the foregoing, if Landlord is delayed in completing
         such construction by May 1, 1998, due to the occurrence of a Force
         Majeure Delay, then the delay in commencement of Tenant's obligation
         to pay rent under the Lease for that portion of the Second Expansion
         Space which is untenable until ten (10) days after substantial
         completion of the Second Expansion Space Finish Work shall constitute
         full settlement of all claims that Tenant may have against Landlord
         based on such a delay.  Furthermore, if Landlord is unable to complete
         the Second Expansion Space Finish Work by May 1, 1998, due to a Tenant
         Delay or due to any other cause related to the acts, neglects,
         failures or omissions of Tenant, Tenant's servants, employees, agents
         or





                                      -5-
<PAGE>   58
         representatives, then Tenant's rental obligations under the Lease with
         respect to the Second Expansion Space shall begin on the date on which
         Landlord would have delivered possession of the Second Expansion Space
         to Tenant absent such Tenant Delay, and such date shall be the Second
         Expansion Space Commencement Date.

                 (iv)     Tenant Delay.  As used herein, the term "Tenant
         Delay" shall mean (i) any delay resulting from Tenant's failure to
         deliver space plans and preliminary construction drawings to Landlord
         on or before (a) February 1, 1997, with respect to the Initial Space,
         (b) May 15, 1997, with respect to the First Expansion Space, or (c)
         September 1, 1997, with respect to the Second Expansion Space
         (respectively, the "Preliminary Plans Date"), or Tenant's failure to
         submit Final Working Drawings to Landlord on or before (a) February
         15, 1997, with respect to the Initial Space, (b) June 15, 1997, with
         respect to the First Expansion Space, or (c) October 1, 1997, with
         respect to the Second Expansion Space; provided, however, if the delay
         in submitting Final Working Drawings is due solely to Landlord
         unreasonably withholding its approval of such drawings, then the delay
         in submitting the Final Working Drawings shall not constitute a Tenant
         Delay; (ii) changes in plans and specifications; or (iii) the
         selection of non-building standard items requiring additional time for
         delivery, installation or fabrication or the presence of installers.
         Tenant shall be responsible for and shall pay to Landlord any and all
         costs and expenses incurred by Landlord and caused by a Tenant Delay.
         Landlord shall not be liable for any damages caused by a Tenant Delay.

                 (v)      Force Majeure Delay.  As used herein, "Force Majeure
         Delay" shall mean any actual delay caused solely by (a) civil
         disturbance; future order or regulation of any government, court or
         regulatory body claiming jurisdiction; the failure of any governmental
         or regulatory body with an appropriate jurisdiction to issue any
         necessary permit, approval or inspection within the time period
         typically required to issue such permit, approval or inspection as of
         the date of this Lease (provided that such delay shall be a Force
         Majeure Delay only to the extent that such delay is caused by or
         within the control of the governmental or regulatory body and not to
         the extent that such delay is caused by or within the control of
         Landlord); or (b) the act of public enemy, war, riot, sabotage,
         blockade, embargo; inability to secure customary materials, supplies
         or labor through ordinary sources by reason of regulation or order of
         any governmental or regulatory body; lightning, earthquake, hurricane,
         tornado, flood, explosion, fire or casualty; and strikes, boycotts or
         labor disturbances and any other causes provided such cause is beyond
         the reasonable control of the party from whom performance is required,
         or any of its contractors or other representatives.

                 [Remainder of page intentionally left blank.]





                                      -6-
<PAGE>   59

         EXECUTED as of the Effective Date.

TENANT:                                LANDLORD:
------                                 -------- 
                                      
PAGEMART WIRELESS, INC.                CRESCENT REAL ESTATE EQUITIES
                                       LIMITED PARTNERSHIP
                                      
                                      
By:  /s/ JOHN D. BELETIC               By:  Crescent Real Estate Equities, Ltd.,
    --------------------------              its General Partner
    Name:   John D. Beletic                                               
          --------------------                                  
    Title:  President and CEO                          
           -------------------        
                                       By:  /s/ JAMES S. WASSEL
                                          -------------------------------------
                                      
                                          Name:  James S. Wassel
                                                -------------------------------
                                          Title: Sr. V.P of Asset Mgmt.
                                                -------------------------------





                                      -7-
<PAGE>   60
                                   EXHIBIT D

                                3333 LEE PARKWAY

                     BUILDING STANDARD JANITORIAL SERVICES


AREAS TO BE SERVICED


OFFICE AREAS

A.       Services to be performed nightly:

         1.      Empty all waste receptacles; remove wastepaper and trash from
                 the premises; replace trash can liners.

         2.      Empty and damp wipe all ashtrays.

         3.      Vacuum all rugs and carpeted areas in offices, including under
                 furniture.

         4.      Hand dust and wipe clean with damp or treated cloth all office
                 furniture, files, fixtures, paneling, window sills, and all
                 other horizontal surfaces; wash windows on inside when
                 necessary.

         5.      Damp wipe and polish all glass furniture tops.

         6.      Remove all finger marks and smudges from all vertical
                 surfaces, including doors, door frames, around light switches
                 and private entrance glass partitions.

         7.      All entry glass next to door will be damp wiped.

B.       Services to be performed as necessary:

         1.      Sweep all stairways weekly, dust handrails and vacuum if
                 carpeted.

         2.      Police all stairwells throughout the entire building weekly
                 and keep in clean condition.

         3.      Damp dust all vinyl covered furniture and vacuum all of the
                 upholstered furniture as needed.

         4.      Dust mini-blinds bi-weekly.





                                      D-1
<PAGE>   61
RESTROOMS

A.       Services to be performed nightly:

         1.      Mop and rinse floors nightly.

         2.      Empty and sanitize all receptacles and sanitary disposals;
                 thoroughly clean and wash at least once per week; replace
                 trash can liners.

         3.      Clean and polish all mirrors, bright work, and enameled
                 surfaces.

         4.      Fill toilet tissue, soap, and towel dispensers.

         5.      Clean flushometers, piping, toilet seat hinges, and other
                 metal work.

B.       Services to be performed as necessary:

         1.      Remove all spots, stains and fingerprints from metal
                 partitions, walls and outside surfaces of all dispensers and
                 soap dishes.

         2.      Vacuum louvers, ventilation grills and dust light fixtures as
                 needed.

         3.      Spray buff all hard surface floors.

         4.      Wash all baseboards.


PUBLIC AREAS

A.       Services to be performed nightly:

         1.      Empty, damp wipe, sift or otherwise service all ashtrays and
                 sand urns.

         2.      Clean and sanitize all drinking fountains; vending machines,
                 table tops, chairs, counter tops and sinks in lunch room
                 facilities.

         3.      Dust all furniture and fixtures.

         4.      Vacuum all carpeted areas.

         5.      Spot clean all hard surface floors.





                                      D-2
<PAGE>   62
         6.      Spot clean all fingerprints from door frames, light switches,
                 push/kick plates and handles.

         7.      Spot clean stains on carpeted areas.

         8.      Clean and polish all metal fittings.

         9.      Dust mop all hard surface floors with a treated dust mop.

         10.     Sweep and/or vacuum entrance mats.

         11.     Keep supply rooms in a clean, neat and orderly condition.

         12.     Glass globes in common areas shall be damp wiped every two
                 weeks.

         13.     All hand railing and woodwork shall be dusted.

B.       Services to be performed as necessary:

         1.      Dust all fire extinguishers.

         2.      Damp dust all ceiling air conditioning diffusers, wall grids,
                 registers and other ventilation louvers.

         3.      Dust the exterior surfaces of lighting fixtures, including
                 glass and plastic enclosures.





                                      D-3
<PAGE>   63
                                   EXHIBIT E

                         BUILDING RULES AND REGULATIONS

         The following rules and regulations shall apply to the Premises, the
Building, the parking garage associated therewith, the Land and the
appurtenances thereto:

         1.      Sidewalks, doorways, vestibules, halls, stairways, and other
similar areas shall not be obstructed by tenants or used by any tenant for
purposes other than ingress and egress to and from their respective leased
premises and for going from one to another part of the Building.

         2.      Plumbing, fixtures and appliances shall be used only for the
purposes for which designed, and no sweepings, rubbish, rags or other
unsuitable material shall be thrown or deposited therein.  Damage resulting to
any such fixtures or appliances from misuse by a tenant or its agents,
employees or invitees, shall be paid by such tenant.

         3.      No signs, advertisements or notices shall be painted or
affixed on or to any windows, doors, or elevators, or other part of the
Building without the prior written consent of Landlord.  No curtains or other
window treatments shall be placed between the glass and the Building standard
window treatments.

         4.      Landlord shall provide and maintain an alphabetical directory
for all tenants in the main lobby of the Building.

         5.      Landlord shall provide all door locks in each tenant's leased
premises, at the cost of such tenant, and no tenant shall place any additional
door locks in its leased premises without Landlord's prior written consent.
Landlord shall furnish to each tenant a reasonable number of keys to such
tenant's leased premises, at such tenant's cost, and no tenant shall make a
duplicate thereof.

         6.      Movement in or out of the Building of furniture or office
equipment, or dispatch or receipt by tenants of any bulky material, merchandise
or materials which require use of elevators or stairways, or movement through
the Building entrances or lobby shall be conducted under Landlord's supervision
at such times and in such a manner as Landlord may reasonably require.  Each
tenant assumes all risks of and shall be liable for all damage to articles
moved and injury to persons or public engaged or not engaged in such movement,
including equipment, property and personnel of Landlord if damaged or injured
as a result of acts in connection with carrying out this service for such
tenant.

         7.      Landlord may prescribe weight limitations and determine the
locations for safes and other heavy equipment or items, which shall in all
cases be placed in the Building so as to distribute weight in a manner
acceptable to Landlord which may include the use of such





                                      E-1
<PAGE>   64
supporting devices as Landlord may require.  All damages to the Building caused
by the installation or removal of any property of a tenant, or done by a
tenant's property while in the Building, shall be repaired at the expense of
such tenant.

         8.      Corridor doors, when not in use, shall be kept closed.
Nothing shall be swept or thrown into the corridors, halls, elevator shafts or
stairways.  No birds, fish, or other animals shall be brought into or kept in,
on or about any tenant's leased premises.  No portion of any tenant's leased
premises shall at any time be used or occupied as sleeping or lodging quarters.

         9.      Tenant shall cooperate with Landlord's employees in keeping
its leased premises neat and clean.  Tenants shall not employ any person for
the purpose of such cleaning other than the Building's cleaning and maintenance
personnel.

         10.     To ensure orderly operation of the Building, no ice, mineral
or other water, towels, newspapers, etc.  shall be delivered to any leased area
except by persons approved by Landlord.

         11.     Tenant shall not make or permit any improper, objectionable or
unpleasant noises or odors in the Building or otherwise interfere in any way
with other tenants or persons having business with them.

         12.     No machinery of any kind (other than normal office equipment)
shall be operated by any tenant on its leased area without Landlord's prior
written consent, nor shall any tenant use or keep in the Building any flammable
or explosive fluid or substance.

         13.     Landlord will not be responsible for lost or stolen personal
property, money or jewelry from tenant's leased premises or public or common
areas regardless of whether such loss occurs when the area is locked against
entry or not.

         14.     No vending or dispensing machines of any kind may be
maintained in any leased premises without the prior written permission of
Landlord.

         15.     All mail chutes located in the Building shall be available for
use by Landlord and all tenants of the Building according to the rules of the
United States Postal Service.





                                      E-2
<PAGE>   65
                                 RIDER NO. 101

                         LEASING RIGHTS AND OBLIGATIONS

         Initial Space.  Effective on the Commencement Date of this Lease (as
defined in Paragraph 3 of the Lease), the Premises shall consist of a minimum
of 30,000 rentable square feet, located on all or a portion of one or more of
the first, seventh, eighth, ninth, tenth, eleventh, or twelfth floors of the
Building; provided that, at Landlord's option, Landlord may substitute the
fifth floor of the Building for the seventh floor of the Building
(collectively, the "Initial Space").  Tenant shall have the right to require
that Landlord construct leasehold improvements in space which contains more
than 30,000 rentable square feet, so long as the additional space (the
"Additional Square Footage") is necessary to complete the remainder of an
entire floor on which a portion of the required 30,000 rentable square feet
(the "Required Square Footage") is located.  In the event that Tenant requires
the construction of leasehold improvements in the Additional Square Footage,
Landlord agrees that Tenant shall not be obligated to pay Basic Rental for the
Additional Square Footage until January 15, 1998; provided that Tenant pays its
proportionate share of Actual Operating Expenses for the Additional Square
Footage, and that the Additional Square Footage shall be deemed to be part of
the Initial Space.  Upon completion of the Finish Work for the Initial Space,
Landlord and Tenant agree to enter into an amendment to this Lease which
modifies the description of the Premises contained in Paragraph 1(c) of this
Lease to reflect the location(s) and Rentable Area of the Initial Space; which
attaches Exhibit A-1, the Floor Plan of the Premises, to this Lease; which
recalculates the Basic Rental amounts shown in Paragraph 1(d) of this Lease
based on the Rentable Area of the Initial Space; and which contains other
appropriate terms and provisions relating to the addition of the Initial Space.

         First Expansion Space.  Effective on the First Expansion Space
Commencement Date (hereinafter defined), the Premises shall be expanded to
include an additional 70,000 square feet of Rentable Area (in excess of the
minimum 30,000 rentable square feet in the Initial Space), which space shall be
located on all or a portion of one or more of the first, seventh, eighth,
ninth, tenth, eleventh, or twelfth floors of the Building; provided that, at
Landlord's option, Landlord may substitute the fifth floor of the Building for
the seventh floor of the Building (collectively, the "First Expansion Space").
The First Expansion Space shall be leased by Tenant subject to the same terms,
covenants and conditions as provided in this Lease for the Premises, except
that the amount of the Finish Allowance (as defined in the Construction
Agreement) provided by Landlord with respect to the First Expansion Space shall
not exceed $15.00 per square foot of Rentable Area contained in the First
Expansion Space.  Except as otherwise provided in the Construction Agreement in
the event of a delay, Tenant's right to occupy the First Expansion Space and
its obligation to pay Basic Rental, Additional Rental, and all other sums due
under this Lease for the First Expansion Space shall commence on the later of
(a) the First Expansion Space Estimated Commencement Date, or (b) ten (10) days
after Landlord's substantial completion of the First Expansion Space Finish
Work, as such terms are defined in the Construction Agreement, but if Tenant
takes possession of the First Expansion
<PAGE>   66
Space for the conduct of business before either such date, then the
commencement date shall be the date Tenant in fact occupies the First Expansion
Space (the "First Expansion Space Commencement Date"), and shall terminate with
the term of this Lease.  From and after the First Expansion Space Commencement
Date, except as otherwise specifically provided herein, any reference to the
term "Premises" in this Lease and any amendments thereto, shall be deemed to
include the First Expansion Space as though originally a part of the Premises
under this Lease, and Tenant's occupancy of the First Expansion Space shall be
subject to all terms and conditions of this Lease, as amended from time to
time.  Upon completion of the Finish Work for the First Expansion Space,
Landlord and Tenant agree to enter into an amendment to this Lease which
modifies the description of the Premises contained in Paragraph 1(c) of this
Lease to include the location(s) and Rentable Area of the First Expansion
Space; which attaches a revised Exhibit A-1, the Floor Plan of the Premises, to
this Lease; which recalculates the Basic Rental amounts shown in Paragraph 1(d)
of this Lease based on the addition of the Rentable Area of the First Expansion
Space; and which contains other appropriate terms and provisions relating to
the addition of the First Expansion Space.

         Second Expansion Space.  Effective on the Second Expansion Space
Commencement Date (hereinafter defined), the Premises shall be expanded to
include an additional 20,000 square feet of Rentable Area (in excess of the
100,000 rentable square feet contained in the Initial Space and the First
Expansion Space), which space shall be located on all or a portion of one or
more of the first, seventh, eighth, ninth, tenth, eleventh, or twelfth floors
of the Building; provided that, at Landlord's option, Landlord may substitute
the fifth floor of the Building for the seventh floor of the Building
(collectively, the "Second Expansion Space").  The Second Expansion Space shall
be leased by Tenant subject to the same terms, covenants and conditions as
provided in this Lease for the Premises, except that the amount of the Finish
Allowance (as defined in the Construction Agreement) provided by Landlord with
respect to the Second Expansion Space shall not exceed $15.00 per square foot
of Rentable Area contained in the Second Expansion Space.  Except as otherwise
provided in the Construction Agreement in the event of a delay, Tenant's right
to occupy the Second Expansion Space and its obligation to pay Basic Rental,
Additional Rental, and all other sums due under this Lease for the Second
Expansion Space shall commence on the later of (a) the Second Expansion Space
Estimated Commencement Date, or (b) ten (10) days after Landlord's substantial
completion of the Second Expansion Space Finish Work, as such terms are defined
in the Construction Agreement, but if Tenant takes possession of the Second
Expansion Space for the conduct of business before either such date, then the
commencement date shall be the date Tenant in fact occupies the Second
Expansion Space (the "Second Expansion Space Commencement Date"), and shall
terminate with the term of this Lease.  From and after the Second Expansion
Space Commencement Date, except as otherwise specifically provided herein, any
reference to the term "Premises" in this Lease and any amendments thereto,
shall be deemed to include the Second Expansion Space as though originally a
part of the Premises under this Lease, and Tenant's occupancy of the Second
Expansion Space shall be subject to all terms and conditions of this Lease, as
amended from time to time.  Upon completion of the Finish Work for the Second
Expansion Space, Landlord and Tenant agree to enter into an amendment to this
Lease which modifies the description of the





                                       2
<PAGE>   67
Premises contained in Paragraph 1(c) of this Lease to include the location(s)
and Rentable Area of the Second Expansion Space; which attaches a revised
Exhibit A-1, the Floor Plan of the Premises, to this Lease; which recalculates
the Basic Rental amounts shown in Paragraph 1(d) of this Lease based on the
addition of the Rentable Area of the Second Expansion Space; and which contains
other appropriate terms and provisions relating to the addition of the Second
Expansion Space.





                                       3
<PAGE>   68
                                 RIDER NO. 201

                                OPTION TO EXPAND

         Tenant shall have the option to lease additional space consisting of
approximately 30,000 rentable square feet located on the third and fourth
floors of the Building, as designated and referred to on Exhibit "201-A"
attached to this Lease as the "Columbia Space", pursuant to the terms and
provisions contained in this Rider No. 201.  The Columbia Space is currently
occupied by Columbia/HCA Healthcare Corporation ("Columbia"), as the
successor-in-interest to Keystone Homehealth Management, Inc. ("Keystone"),
under that certain Office Lease dated January 5, 1996, by and between Keystone
and Landlord (the "Columbia Lease"), which expires on January 31, 1999 (the
"Columbia Expiration Date").  Under the Columbia Lease, both Landlord and
Columbia have the right to terminate the Columbia Lease, at any time, by giving
the other party six (6) months prior written notice.  Columbia also has the
right to extend the term of the Columbia Lease for one (1) additional period of
three (3) years by giving Landlord written notice at least nine (9) months
before the Columbia Expiration Date.  Tenant shall have the option to lease the
Columbia Space, as it becomes available, pursuant to the following terms and
conditions:

         (a)     Events of Availability:

                 (1)      Termination by Columbia.  In the event Columbia
         elects to terminate the Columbia Lease by giving Landlord six (6)
         months prior written notice, Landlord shall, upon receipt of such
         notice, promptly notify Tenant of such fact and of the date such
         termination shall become effective.  Upon such a termination, Tenant
         shall have the right to lease all or a portion of the Columbia Space,
         so long as Tenant leases a minimum of 10,000 rentable square feet of
         the Columbia Space.  Tenant shall have a period of thirty (30) days
         after receipt of Landlord's notice to notify Landlord whether Tenant
         elects to exercise its right to lease all or a portion of the Columbia
         Space.  If Tenant elects to lease only a portion of the Columbia
         Space, then Tenant shall specify in the notice the amount of rentable
         square feet which Tenant desires to lease (which amount cannot be less
         than 10,000 rentable square feet), and Landlord shall have the right
         to determine the location of such portion.  If Tenant waives its right
         to lease all or a portion of the Columbia Space (either by giving
         written notice thereof or by failing to give any notice to Landlord
         within the required thirty (30) day period), this Option to Expand
         shall thereafter be null, void and of no further force or effect.

                 (2)      Expiration of the Columbia Lease.  In the event
         Columbia waives its right to extend the term of the Columbia Lease,
         either by giving written notice thereof to Landlord or by failing to
         give any notice to Landlord by April 30, 1998, Landlord shall promptly
         notify Tenant of such fact.  Upon such an expiration, Tenant shall
         have the right to lease all or a portion of the Columbia Space, so
         long as Tenant leases a minimum of 10,000 rentable square feet of the
         Columbia Space.  Tenant shall have a period of thirty (30) days after
         receipt of Landlord's notice to notify Landlord whether Tenant elects
         to exercise its right to lease all or a portion of the Columbia Space.
         If Tenant elects to lease only a portion of the Columbia Space, then
         Tenant shall specify
<PAGE>   69
         in the notice the amount of rentable square feet which Tenant desires
         to lease (which amount cannot be less than 10,000 rentable square
         feet), and Landlord shall have the right to determine the location of
         such portion.  If Tenant waives its right to lease all or a portion of
         the Columbia Space (either by giving written notice thereof or by
         failing to give any notice to Landlord within the required thirty (30)
         day period), this Option to Expand shall thereafter be null, void and
         of no further force or effect.

                 (3)      Extension of the Columbia Lease With the Termination
         Right.  In the event Columbia elects to exercise its right to extend
         the term of the Columbia Lease through and including January 31, 2002,
         subject to all the terms, covenants and conditions of the Columbia
         Lease, including, but not limited to, the right of either Landlord or
         Columbia to terminate the Columbia Lease upon six (6) months prior
         written notice to the other party, Landlord shall promptly notify
         Tenant of such fact.  At any time after receipt of Landlord's notice,
         if Tenant requires additional space in the Building and desires to
         expand into the Columbia Space, then Tenant shall have the right to
         request that Landlord exercise its termination right with respect to
         the Columbia Space, by giving Landlord written notice at least seven
         (7) months prior to the date on which Tenant desires to commence
         construction on the Columbia Space.  Landlord will then notify
         Columbia of the termination of the Columbia Lease.  In the event
         Columbia exercises its termination right during the extended term of
         the Columbia Lease, Landlord shall notify Tenant of such fact pursuant
         to the terms and conditions of subparagraph (1) above.

                 (4)      Extension of the Columbia Lease Without the
         Termination Right.  In the event Columbia notifies Landlord of its
         desire to exercise its right to extend the term of the Columbia Lease
         through and including January 31, 2002, subject to all the terms,
         covenants and conditions of the Columbia Lease, except for the right
         of either Landlord or Columbia to terminate the Columbia Lease upon
         six (6) months prior written notice to the other party, Landlord shall
         promptly notify Tenant of such fact.  Tenant shall have a period of
         thirty (30) days after receipt of Landlord's notice to notify Landlord
         whether Tenant elects to exercise its right to lease the entire
         Columbia Space.  If Tenant waives its right to lease the Columbia
         Space (either by giving written notice thereof or by failing to give
         any notice to Landlord within the required thirty (30) day period),
         Tenant shall be deemed to have waived its right to exercise this
         Option to Expand through and including January 31, 2002.  Tenant shall
         have the right to lease the Columbia Space after January 31, 2002,
         provided that Tenant gives Landlord written notice no later than
         January 31, 2001, of Tenant's desire to lease the Columbia Space upon
         the expiration of the extended term of the Columbia Lease.

         (b)     Tenant's Exercise of Its Option to Expand.  Tenant's Option to
Expand provided herein is subject to the condition that on the date Tenant
notifies Landlord of Tenant's election to lease the Columbia Space and on the
Columbia Space Commencement Date (hereinafter defined), (i) no event of
default, as defined in Paragraph 13 of this Lease, shall have occurred, and
(ii) Tenant occupies no less than 100,000 rentable square feet in the Building.
If the foregoing conditions are met, and if Tenant timely notifies Landlord of
Tenant's election to exercise its Option to Expand upon one (1) of the events
of availability of the Columbia Space





                                       2
<PAGE>   70
set forth in paragraph (a) above, then Landlord and Tenant shall enter into a
written agreement modifying and supplementing this Lease and specifying that
the Columbia Space is part of the Premises under this Lease and containing
other appropriate terms and provisions relating to the addition of such space
to this Lease (including specifically any increase of rent as a result of such
addition) as follows:  Tenant shall lease the Columbia Space for a term
commencing on the date of substantial completion of the leasehold improvements
to the Columbia Space, but in no event later than seventy-five (75) days after
Columbia vacates the Columbia Space (the "Columbia Space Commencement Date"),
and ending contemporaneously with the expiration of the term of this Lease
(unless sooner terminated pursuant to the terms and provisions of this Lease).
Tenant's obligation to pay Basic Rental, Additional Rental, and all other sums
due under this Lease for the Columbia Space shall commence on the Columbia
Space Commencement Date, and shall terminate with the term of this Lease.  If
the Columbia Space Commencement Date occurs during the first three (3) years of
the Lease Term, then (i) the Basic Rental for the Columbia Space shall be at
the same rental rate then in effect for the Premises pursuant to the Lease,
which Basic Rental shall be increased as provided in and under the Lease, and
(ii) the amount of the tenant improvement allowance given for the Columbia
Space shall be reduced by $0.12 for each month of the Lease Term that has
expired prior to the Columbia Space Commencement Date (for example, if the
Columbia Space Commencement Date is ten (10) months after the Commencement Date
of the Lease, then the tenant improvement allowance payable by Landlord with
respect to the Columbia Space shall not exceed $13.80 per square foot of
Rentable Area contained in the Columbia Space).  If the Columbia Space
Commencement Date occurs after the third anniversary of the Commencement Date
of the Lease, then (i) the Basic Rental for the Columbia Space shall be at the
prevailing rate for comparable space in the Building on the Columbia Space
Commencement Date, and (ii) the amount of the tenant improvement allowance
given for the Columbia Space shall be at the prevailing rate for comparable
space in the Building on the Columbia Space Commencement Date.  Landlord shall
not be liable for the failure to give possession of the Columbia Space upon the
occurrence of an event of availability as set forth in paragraph (a) above by
reason of the holding over or retention of possession of any tenant, tenants or
occupants, and such failure shall not impair the validity of this Lease, or
extend the Lease Term, but the rent for the Columbia Space shall be abated
until possession is delivered to Tenant and such abatement shall constitute
full settlement of all claims that Tenant might otherwise have against Landlord
by reason of such failure to give possession of the Columbia Space to Tenant on
such date.  Any assignment or subletting by Tenant pursuant to Paragraph 9 of
this Lease, other than to a Fortune 500 company or an Affiliate, if any, shall
terminate the option of Tenant contained herein.  If Tenant shall exercise its
right of expansion as provided in this Rider No. 201, and shall occupy the
Columbia Space during the initial Lease Term, then, for purposes of the
extension of the Lease Term pursuant to an option to extend this Lease, if any,
the Columbia Space shall be considered to be a part of the Premises under this
Lease, and the Basic Rental for the Columbia Space shall be adjusted as
provided in and under such option to extend.





                                       3
<PAGE>   71
                                 RIDER NO. 301

                             RIGHT OF FIRST REFUSAL

         Provided this Lease is then in full force and effect and no event of
default, as defined in Paragraph 13 of this Lease, shall have occurred, Tenant
shall have the right of first refusal as hereinafter described to lease that
portion of the space to be leased to a prospective tenant (the "Offered Space")
which is all or part of the third, fourth, fifth, and/or sixth floor of the
Building (collectively, the "Right of First Refusal Space"), as shown and
designated on Exhibit "301-A" attached to this Lease as the "Right of First
Refusal Space", at such time as Landlord engages in negotiations with a
prospective tenant, exercisable at the following times and upon the following
conditions:

         1.      If Landlord enters into negotiations with a prospective tenant
to lease the Offered Space, Landlord shall notify Tenant of such fact and shall
include in such notice the rent, term, and other terms (including finish out)
at which Landlord is prepared to offer such Offered Space to such prospective
tenant.  Tenant shall have a period of five (5) business days from the date of
delivery of the notice to notify Landlord whether Tenant elects to exercise the
right granted hereby to lease the Offered Space on terms which result in the
same economic benefit to Landlord as the rent, term, and other terms specified
in the notice.  With respect to the Columbia Space only (as defined in Rider
No.  201 attached to this Lease), Tenant shall have the option to lease the
Offered Space either (i) upon the same rent, term, and other terms specified in
the notice, or (ii) for a term which expires upon the expiration date of this
Lease and at a rate and other terms which collectively provide the same
economic benefit to Landlord as the rent, term, and other terms specified in
the notice.  With respect to the Columbia Space only, Tenant shall have a
period of five (5) business days from the date of delivery of the notice to
notify Landlord whether Tenant elects to exercise the right granted hereby to
lease the Offered Space and under which of the foregoing options Tenant elects
to lease the Offered Space.  If Tenant fails to give any notice to Landlord
within the required five (5) business day period, Tenant shall be deemed to
have waived its right to lease the Offered Space.

         2.      If Tenant so waives its right to lease the Offered Space
(either by giving written notice thereof or by failing to give any notice),
Landlord shall have the right to lease the Offered Space to the prospective
tenant, on terms which result in the same economic benefit to Landlord as the
terms contained in Landlord's notice to Tenant, and upon the execution of such
lease between Landlord and the prospective tenant this Right of First Refusal
as to the Offered Space shall thereafter be null, void and of no further force
or effect.

         3.      If Landlord does not enter into a lease with such prospective
tenant covering the Offered Space, or if Landlord offers the Offered Space to
the prospective tenant on terms which do not result in the same economic
benefit to Landlord as the terms contained in Landlord's notice to Tenant, then
Landlord shall not thereafter engage in other lease negotiations with respect
to the Right of First Refusal Space without first complying with the provisions
of this Rider No. 301.
<PAGE>   72
         4.      Upon the exercise by Tenant of its right of first refusal as
provided in this Rider No. 301, Landlord and Tenant shall, within twenty (20)
days after Tenant delivers to Landlord notice of its election, enter into a
lease or an amendment to this Lease covering the Offered Space for the rent,
for the term, and containing such other terms and conditions as Landlord
notified Tenant pursuant to paragraph 1 above.

         5.      Any assignment or subletting by Tenant pursuant to Paragraph 9
of this Lease, other than to a Fortune 500 company or an Affiliate, if any,
shall terminate the right of first refusal of Tenant contained herein.





                                       2
<PAGE>   73
                                 RIDER NO. 401

                                OPTION TO EXTEND

         Tenant at its option may extend the term of this Lease for one (1)
extension term of five (5) years by serving written notice thereof upon
Landlord at least twelve (12) months before the expiration of the initial lease
term, provided that at the time of such notice and at the commencement of such
extended term, no event of default, as defined in Paragraph 13 of this Lease,
shall have occurred.  Upon the service of such notice and subject to the
conditions set forth in the preceding sentence, this Lease shall be extended
without the necessity of the execution of any further instrument or document.
Such extended term shall commence upon the expiration date of the initial lease
term, expire upon the annual anniversary of such date five (5) years
thereafter, and be upon the same terms, covenants, and conditions as provided
in this Lease for the initial term, except that the Basic Rental payable during
the extended term shall be at the prevailing rate for comparable space in the
Building, at the commencement of such extended term, which new Basic Rental
shall be adjusted as provided in and under this Lease.  Payment of all
additional rent and other charges required to be made by Tenant as provided in
this Lease for the initial term shall continue to be made during the extended
term.  Any termination of this Lease during the initial term shall terminate
all rights of extension hereunder.  Any assignment or subletting by Tenant
pursuant to Paragraph 9 of this Lease, other than to a Fortune 500 company or
an Affiliate, if any, shall terminate the option of Tenant contained herein.
Notwithstanding the foregoing, in no event shall the Basic Rental for the
extension term be less than the Basic Rental during the last year of the
initial term.
<PAGE>   74
                                 RIDER NO. 501

                               TERMINATION OPTION

         Tenant shall have the option to terminate this Lease on the last day
of any month after the date which is five (5) years and eight (8) months after
the Commencement Date of this Lease (as applicable, the "Termination Date");
provided that (i) Tenant gives Landlord at least nine (9) months prior written
notice to terminate, and (ii) Tenant is not in default under the Lease at the
time of the giving of such notice nor on the Termination Date.  Additionally,
Tenant's right to terminate hereunder is conditioned upon the payment in full
by Tenant, on or before the Termination Date, of (a) all Basic Rental,
Additional Rental and other sums owed by Tenant under the Lease through and
including the Termination Date; and (b) an amount equal to the sum of (i) the
amount obtained by multiplying $5,685,000.00 by a fraction having as its
numerator, the number of months remaining in the initial Lease Term, and having
as its denominator, the number sixty (60), plus (ii) the unamortized cost of
all tenant improvement allowances, leasing commissions and other transaction
costs actually paid by Landlord in connection with this Lease with interest
thereon at the rate of twelve and one-half percent (12.5%) per annum
(collectively, the "Termination Payment").  After Landlord's receipt of the
Termination Payment, and so long as Tenant has surrendered the Premises in the
condition required under this Lease, neither party shall have any rights,
liabilities or obligations under this Lease for the period accruing after the
Termination Date, except those which, by the provisions of this Lease,
expressly survive the termination of this Lease.
<PAGE>   75
                                   EXHIBIT F

                           ROOFTOP LICENSE AGREEMENT


         THIS ROOFTOP LICENSE AGREEMENT (this "Agreement") is entered into as
of the ____ day of _________, 1996, by and between CRESCENT REAL ESTATE
EQUITIES LIMITED PARTNERSHIP ("Licensor") and PAGEMART WIRELESS, INC.
("Licensee").

                                   RECITALS:

         A.      Licensee and Licensor entered into that certain Office Lease
dated _________________________ (as amended, the "Lease") pursuant to which
Licensee has leased from Licensor certain premises in the building (the
"Building") located in the project commonly known as "3333 Lee Parkway" and
located at 3333 Lee Parkway, Dallas, Dallas County, Texas (the "Project").

         B.      Licensee desires to license from Licensor certain space
located on the roof of the Building for the installation of the Communications
Equipment (defined below) of Licensee.

                                   AGREEMENT:

         NOW, THEREFORE, in consideration of the sum of Ten Dollars ($10.00),
the mutual promises set forth herein and in the Lease, and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged and confessed, Licensor and Licensee hereby agree as follows:

         1.      License of Equipment Area.  Subject to the terms and
conditions hereof, Licensor hereby licenses to Licensee, and Licensee hereby
licenses from Licensor, the right to use approximately ______________ square
feet of space located on the roof of the Building (the "Equipment Area") for
the installation and operation of the Communications Equipment.  The location
of the Equipment Area is depicted on Exhibit A attached hereto and incorporated
herein by reference.  Licensee accepts the Equipment Area in its "as-is"
condition and acknowledges that Licensor makes no representations or warranties
whatsoever with respect thereto.

         2.      Term.  The term of this Agreement (the "Term") shall commence
on _______________________, 19____, and shall expire on the date of the
expiration or termination of the Lease, unless sooner terminated pursuant to
the provisions hereof.  This Agreement may be cancelled at any time by Licensor
delivering to Licensee  ____________ (____) days prior written notice of such
cancellation.  Licensee may terminate this Agreement at any time by delivering
to Licensor ninety (90) days prior written notice of such termination.

         3.      License Fee; Electrical Costs.  As consideration for the
license granted to Licensee herein, Licensee agrees to pay to Licensor, in
advance without deduction or setoff, and on the first day of the month, a
license fee (the "License Fee") in the amount of $_______________
<PAGE>   76
_ per month.  Such payments shall be made in the same manner as Licensee's
rental payments are made under the Lease, or at such other place as may from
time to time be designated by Licensor.  In the event that the Term begins or
ends on a day other than the first or last day of a month, as applicable, the
License Fee for such period shall be prorated on a per diem basis.  The License
Fee for the first calendar month or portion thereof shall be paid concurrently
with the execution of this Agreement.  Licensee shall also pay to Licensor as
an additional license fee hereunder, within fifteen (15) days after the receipt
of an invoice therefor, the costs incurred by Licensor in providing electrical
service to the Equipment Area.

         4.      Security Deposit.  Licensee shall deposit with Licensor a
security deposit (the "Security Deposit") in the amount of $__________
contemporaneously with the execution hereof.  Licensor shall hold the Security
Deposit without interest, and the same shall not be considered a prepayment of
the License Fee nor a measure of Licensor's damages in case of default by
Licensee.  Licensor may apply the Security Deposit to the extent necessary to
make good any payment arrearages, to pay the cost of remedying Licensee's
default or to reimburse Licensor for expenditures made or damages suffered as a
consequence of Licensee's default.  Following any such application of the
Security Deposit, Licensee shall pay to Licensor on demand the amount so
applied in order to restore the Security Deposit to its original amount.  Any
remaining balance of the Security Deposit shall be refundable to Licensee
within thirty (30) days after the expiration or earlier termination of this
Agreement.

         5.      Communications Equipment.  Licensee shall have the right to
install and maintain in the Equipment Area, at Licensee's sole cost and
expense,[ _________ (____) MICROWAVE DISHES (NOT TO EXCEED SIX (6) FEET IN
DIAMETER), ___________ (_____) DIRECTIONAL PANEL OR OMNIDIRECTIONAL WHIP RADIO
COMMUNICATIONS ANTENNAE] and any necessary connecting equipment or cabling
(collectively, the "Communications Equipment").

         6.      Compliance With Legal Requirements.  The installation,
maintenance, use, removal and any relocation of the Communications Equipment
shall comply with all laws, rules, regulations, restrictions, restrictive
covenants and architectural guidelines applicable to the Project and/or the
Communications Equipment, as the same may be amended from time to time (the
"Legal Requirements"), and Licensee shall obtain, at its sole cost and expense,
all approvals, consents, licenses, authorizations and permits required under
the Legal Requirements in connection with any such installation, maintenance,
use, removal or relocation.

         7.      Installation of Communications Equipment.  Before beginning
the installation of the Communications Equipment, Licensee shall deliver to
Licensor final plans and specifications setting forth in detail the design,
location, size, weight, color scheme, material composition, method of
installation, and frequency of the Communications Equipment for Licensor's
review and approval, together with evidence reasonably satisfactory to Licensor
that all Legal Requirements have been satisfied.  Licensor's approval of any
such plans and specifications shall not constitute a representation or warranty
by Licensor that such plans and specifications comply with the Legal
Requirements.  Such compliance shall be the sole responsibility of Licensee,
but Licensor shall, at Licensee's request and expense, use reasonable efforts
to assist Licensee in





                                      F-2
<PAGE>   77
complying therewith.  Upon approval by Licensor of the plans and specifications
therefor and the location thereof, Licensee may install the Communications
Equipment in the Equipment Area, provided that such work is coordinated with
and completed in accordance with the instructions of Licensor and Licensor's
roofing contractor, and is performed in a good and workmanlike manner, in
accordance with all Legal Requirements and the plans and specifications
therefor, and in a manner so as not to damage the Project or materially
interfere with the use of any portion of the Project while such installation is
taking place.  Except to the extent otherwise directed by Licensor, Licensee
shall, at Licensee's sole cost and expense, connect the Communications
Equipment to the Premises through cables in conduit in the utility chases in
the Building and to the Building lightning protection system and electrical
service, and install a submeter for the providing of electrical service to the
Equipment Area.

         8.      Equipment Changes.  From time to time Licensee shall have the
right, with the prior written approval of Licensor and at Licensee's sole cost
and expense, to install, maintain, repair and replace the Communications
Equipment or components thereof, including, without limitation, electrical and
communications wires, cables and other pipes, conduits and lines linking
various components of the Communications Equipment with other components
thereof.  In exercising the rights granted hereunder, Licensee shall comply
with all Legal Requirements and with the reasonable rules and regulations of
the Building which may from time to time be prescribed by Licensor.

         9.      Interference.  Licensee acknowledges and agrees that its use
of the rooftop of the Building is of a non-exclusive nature and that Licensor
has the right to grant other licenses, leases or rights of use, of any kind or
nature, to parties other than Licensee.  The Communications Equipment shall be
of such type and frequencies, and shall be operated in a manner, that will not
cause measurable frequency interference with the business or operations of any
tenant, occupant or other licensee of the Building, including the operation of
transmitting and receiving devices operated within their assigned frequencies
and within Federal Communications Commission ("FCC") rules and regulations.
Licensor shall use reasonable efforts to ensure that any rights to use the roof
of the Building (including, without limitation, any rights to install other
antenna equipment), or any other lease or license for use of the Building for
communications uses, granted to third parties hereafter shall not result in
measurable frequency interference with the Communications Equipment, and
Licensor shall use reasonable diligence to prevent or stop such interference
upon receiving notice thereof from Licensee.  Licensor and Licensee agree that
Licensor (or, if requested by Licensee, an independent third party qualified in
the communications industry, provided any fees charged by such third party
shall be paid by Licensee) shall arbitrate any disputes between Licensee and
other tenants, occupants or licensees of the Building concerning alleged
interference with the operation of the Communications Equipment, whether
claimed to be caused by Licensee or such other tenants, occupants or licensees.
Licensee shall be bound by Licensor's (or, if applicable, the third party's)
determination in such disputes.  In determining such disputes, the underlying
assumption shall be that the device installed later in time shall be required
to have frequencies and operating characteristics that minimize interference
with devices installed prior in time, but that all devices shall be designed,
maintained and upgraded to minimize interference with other





                                      F-3
<PAGE>   78
devices in accordance with industry standards as they change from time to time.
In the event the Communications Equipment causes interference to any device
installed prior in time, Licensee will take all steps necessary to correct and
eliminate the interference.  If said interference cannot be eliminated within a
reasonable length of time, Licensee agrees, at the request of Licensor, to
remove the Communications Equipment from the Project and this Agreement shall
then terminate without further obligation on the part of Licensor or Licensee,
except as expressly provided otherwise herein.

         10.     Access to Equipment Area.  Licensee shall have access to the
Equipment Area twenty-four (24) hours per day, each and every day during the
Term; provided, that (i) Licensee shall provide to Licensor at least two (2)
hours advance notice of any need for access, and (ii) a representative of
Licensor may accompany Licensee on the roof of the Building during such access.
Access to the Equipment Area may be arranged through Licensor's property
management personnel or, after the normal business hours for the Building,
through Licensor's security personnel at the Building.  In the event that
Licensee requests access to the Equipment Area at times other than the normal
business hours for the Building, Licensee shall compensate Licensor for
reasonable trip charges and overtime charges resulting from employees or agents
of Licensor making trips to the Building to provide such after hours access.

         11.     Service Interruptions; Equipment Malfunctions.  Licensor shall
not be liable to Licensee for the interruption or suspension of electrical
service to the Communications Equipment.  In addition, Licensor shall not be
liable or responsible for any alleged malfunction or non-functioning of the
Communications Equipment or for the repair, maintenance or any loss of, or
damage to, such equipment.

         12.     Licensee's Covenants.  Licensee covenants and agrees as
                 follows:

                 (a)      Condition of Equipment; Repairs.  Licensee shall use,
maintain, and operate the Communications Equipment in a good and safe condition
and in accordance with all Legal Requirements, and shall keep the Equipment
Area free from all trash, debris and waste resulting from the use thereof by
Licensee.  Licensee shall repair all damage caused to the Project by the
installation, use, maintenance, relocation or removal of the Communications
Equipment and shall, upon its removal, restore the Equipment Area to its
condition immediately before the installation thereof, ordinary wear and tear
excepted.  If Licensee fails to do so within five (5) days after Licensor's
request, Licensor may perform such work and Licensee shall reimburse Licensor
for all reasonable costs incurred in connection therewith within fifteen (15)
days after Licensor's request therefor, which reimbursement obligation of
Licensee shall survive the expiration or earlier termination of this Agreement.

                 (b)      Costs; Liens.  Licensee shall pay or cause to be paid
all costs for materials provided or work performed by or at the direction of
Licensee related to the Communications Equipment or the Equipment Area.  In the
event of any claim of any kind or nature against Licensor or, if other than
Licensor, the owner of the property on which the Building is located
(including, but not limited to, mechanic's liens), arising out of the failure
of payment or





                                      F-4
<PAGE>   79
performance of an obligation required of Licensee under this Agreement,
Licensee shall be solely responsible to adjust, settle and/or pay any and all
such claims, in full, at the sole cost and expense of Licensee.  If a
mechanic's lien is filed against the Building or the Project as a result of
such claim, Licensee shall bond against or discharge any such liens within five
(5) days after notice from Licensor.  In the event Licensor or, if other than
Licensor, the owner of the property on which the Building is located sustains
any loss or damage by reason of any such claim, Licensee will fully indemnify
Licensor and/or said owner for any such loss or damage, including reasonable
attorneys' fees incurred in connection therewith, which indemnity obligation of
Licensee shall survive the expiration or earlier termination of this Agreement.

                 (c)      Taxes.  Licensee shall pay any sales, use and
personal property taxes assessed on, or any portion of such taxes attributable
to, the Communications Equipment.  In addition, Licensee shall pay, as an
additional license fee hereunder, any increase in real property taxes levied
against the Building (excluding any additional taxes that relate to the period
prior to the commencement date of the Term) which is directly attributable to
Licensee's use of the Equipment Area.

                 (d)      Surrender; Removal of Equipment.  Upon the expiration
or earlier termination of this Agreement, Licensee shall remove the
Communications Equipment from the Project and peaceably surrender the Equipment
Area to Licensor in the condition the same was in at the commencement of this
Agreement, ordinary wear and tear excepted.  In addition, Licensee shall remove
the Communications Equipment from the Project within ten (10) days after the
termination of Licensee's right to possess the premises therein.  If Licensee
fails to perform any such removal work, Licensor may do so and store or dispose
of the Communications Equipment in any manner Licensor deems appropriate
without liability to Licensee.  Licensee shall reimburse Licensor for all
reasonable costs incurred by Licensor in connection therewith within fifteen
(15) days after Licensor's request therefor, which reimbursement obligation of
Licensee shall survive the expiration or earlier termination of this Agreement.

                 (e)      Increases in Operating Expenses or Insurance.  If
Licensee's installation or operation of the Communications Equipment results in
an increase in Licensor's operating expenses (including taxes) or insurance
premiums related to the Project at any time during the Term, Licensee shall be
responsible for the payment of the amount of such increase which is
attributable to such installation or operation, as reasonably determined by
Licensor.  Licensee shall pay any such amounts to Licensor within ten (10) days
after receipt of an invoice therefor. Licensee shall not install or operate the
Communications Equipment in a manner that results in the cancellation or
termination of Licensor's insurance.

                 (f)      Relocation Expenses.  Licensee shall pay all costs
associated with any relocation of the Communications Equipment required by any
governmental authority.





                                      F-5
<PAGE>   80
         13.     Certain Rights Reserved by Licensor.  Licensor shall have the
                 following rights:

                 (a)      Right to Relocate Equipment.  At any time after the
execution of this Agreement and on fifteen (15) days prior written notice,
Licensor may substitute for the Equipment Area other space on the roof of the
Building (the "New Equipment Area"), in which event the New Equipment Area
shall be deemed to be the Equipment Area for all purposes hereunder.  Licensor
shall reimburse Licensee for Licensee's reasonable out-of-pocket costs in
connection with the relocation of the Communications Equipment to the New
Equipment Area.

                 (b)      Screening of Equipment.  At any time during the Term,
Licensor may require that Licensee install, at Licensee's sole cost and
expense, a screening device to ensure that the Communications Equipment cannot
be viewed by the public.  Such screening device shall comply with all Legal
Requirements and any requirements regarding the construction, maintenance and
removal of such screening device that Licensor may establish from time to time.
Licensee shall obtain Licensor's prior written approval of all plans and
specifications for such screening device.

         14.     Licensee's Insurance.

                 (a)      No construction, alteration or removal operations
shall be initiated by Licensee unless Licensee has first obtained builders risk
insurance in limits and with coverage reasonably acceptable to Licensor.

                 (b)      At all times during the Term, Licensee shall maintain
in force, at its expense, a policy of public liability insurance insuring
Licensee with a combined single limit of at least $2,000,000.00 for injury or
death or property damage, with an umbrella policy providing excess liability
coverage of not less than $3,000,000.00 insuring against the liability of
Licensee arising out of or in connection with its installation, maintenance,
operation and use of the Telecommunications Equipment and/or the provision of
services at the Equipment Area.

                 (c)      At all times during the Term, Licensee shall maintain
workers compensation insurance covering Licensee's employees entering the
Building.

                 (d)      At all times during the Term, Licensee shall maintain
fire and casualty insurance on Licensee's personal property for the replacement
cost thereof.

                 (e)      All insurance required to be maintained by Licensee
hereunder shall be issued by an insurance company licensed to do business in
the State of Texas, shall name Licensor and its managing agent, if any, as
additional insureds, and shall insure Licensee's performance of its obligations
under the indemnity provisions of this Agreement.  Licensee's insurance shall
contain provisions providing that such insurance shall be primary insurance
insofar as Licensor and Licensee are concerned, with any other insurance
maintained by Licensor being excess and non-contributing with the insurance of
Licensee required hereunder.  Licensee shall provide a certificate evidencing
such insurance to Licensor prior to





                                      F-6
<PAGE>   81
commencement of any construction pursuant to this Agreement and upon renewals
of such policies prior to the renewal date.  Licensor shall have the right to
review the adequacy of the limits of insurance coverage required of Licensee
hereunder, and make changes it deems necessary, not less than every year.

         15.     Waiver of Subrogation.  It is the intent of Licensor and
Licensee not to hold each other responsible for that portion of any loss or
damage paid or reimbursed by an insurer of Licensor or Licensee under any fire,
extended coverage or other property insurance policy maintained by Licensee
with respect to the Equipment Area or by Licensor with respect to the Building.
Therefore, with respect to the amount of any damage, loss, claim or liability
paid or reimbursed by an insurer under any fire, extended coverage or property
insurance policy maintained by Licensee with respect to the Equipment Area, or
Licensor with respect to the Building, Licensor, Licensee and all parties
claiming under them each mutually release and discharge each other from such
damages, losses, claims or liabilities, no matter how caused, including
negligence, and each waives any right of recovery from the other including, but
not limited to, claims for contribution or indemnity, which might otherwise
exist on account thereof.  Any fire, extended coverage or property insurance
policy maintained by Licensee with respect to the Equipment Area, or Licensor
with respect to the Building, shall contain, in the case of Licensee's
policies, a waiver of subrogation provision or endorsement in favor of
Licensor, and in the case of Licensor's policies, a waiver of subrogation
provision or endorsement in favor of Licensee, or, in the event that such
insurers cannot or will not attach such waiver of subrogation provisions or
endorsements, Licensee and Licensor shall obtain the approval and consent of
their respective insurers, in writing, to the terms of this Agreement.  Neither
Licensee nor its insurers shall be entitled to receive any contribution from
any insurance policies separately maintained by Licensor, and Licensee agrees
to indemnify, protect, defend and hold harmless Licensor and any of Licensor's
insurers from any claim, suit or cause of action asserted or brought by
Licensee's insurers for, on behalf of, or in the name of Licensee, including
but not limited to, claims for contribution, indemnity or subrogation.  The
mutual releases, discharges and waivers contained in this provision shall apply
EVEN IF THE LOSS OR DAMAGE TO WHICH THIS PROVISION APPLIES IS CAUSED SOLELY OR
IN PART BY THE NEGLIGENCE OF LICENSOR OR LICENSEE.

         16.     INDEMNITY.  LICENSEE HEREBY AGREES TO INDEMNIFY, DEFEND AND
HOLD HARMLESS LICENSOR AND ITS MANAGING AGENT, AND THEIR RESPECTIVE PARTNERS,
DIRECTORS, OFFICERS, EMPLOYEES, AGENTS, AFFILIATES AND SUCCESSORS-IN-INTEREST
(COLLECTIVELY AND TOGETHER WITH LICENSOR, THE "LICENSOR PARTIES") FROM AND
AGAINST ALL LIABILITY, LOSS, DAMAGE, COST OR EXPENSE, INCLUDING ATTORNEYS'
FEES, ON ACCOUNT OF ANY CLAIMS OF ANY NATURE WHATSOEVER (INCLUDING CLAIMS OR
LIENS OF LABORERS OR MATERIALMEN OR OTHERS) FOR WORK PERFORMED, MATERIALS OR
SUPPLIES FURNISHED, DAMAGE TO PROPERTY OR INJURY TO PERSONS CAUSED BY THE
NEGLIGENCE OR MISCONDUCT OF LICENSEE OR LICENSEE'S AGENTS, SERVANTS, OR
EMPLOYEES OR ANY OTHER PERSONS ENTERING UPON THE EQUIPMENT AREA OR THE BUILDING
UNDER THE EXPRESS





                                      F-7
<PAGE>   82
OR IMPLIED INVITATION OF LICENSEE, OR WHERE SUCH INJURY IS THE RESULT OF THE
VIOLATION OF THE PROVISIONS OF THIS AGREEMENT BY ANY SUCH PERSON OR CAUSED BY
THE CONSTRUCTION, INSTALLATION, ALTERATION, MAINTENANCE, REPAIR, RELOCATION OR
USE OF THE COMMUNICATIONS EQUIPMENT.  LICENSEE'S OBLIGATIONS AND LIABILITIES
UNDER THIS PARAGRAPH SHALL SURVIVE THE EXPIRATION OR TERMINATION OF THIS
AGREEMENT.

         17.     Hazardous Materials.  Licensee shall not cause or permit the
storage, use, generation or disposition of any Hazardous Materials (as
hereinafter defined) in the Equipment Area without the prior written consent of
Licensor.  Licensee hereby agrees to indemnify, defend and hold harmless the
Licensor Parties from and against all fines, suits, procedures, claims and
actions of every kind, and all costs associated therewith (including attorneys'
and consultants' fees) arising out of or in any way connected with any deposit,
spill, discharge or other release of Hazardous Materials that occurs in or from
the Equipment Area, or which arises from Licensee's use or occupancy of the
Equipment Area.  Licensee's obligations and liabilities under this paragraph
shall survive the expiration or termination of this Agreement.  For purposes of
this Agreement, the term "Hazardous Materials" means any explosives,
radioactive materials or other hazardous substances which are governed by any
federal, state or local statute, law, ordinance, code, rule, regulation or
decree applicable to the Project.

         18.     Default and Remedies.  Licensor and Licensee hereby agree that
time is of the essence with respect to the payment by Licensee of the License
Fee and any other monetary obligation of Licensee under this Agreement and the
performance by Licensee of the terms, covenants and conditions of this
Agreement.  If Licensee fails to pay the License Fee or other monetary
obligation under this Agreement when due or otherwise defaults in the
performance of any of the terms, covenants and conditions of this Agreement,
Licensor may, at its option and in addition to all other remedies available
under applicable law, terminate this Agreement.  In the event of such a
default, all payments previously made by Licensee under this Agreement will
remain the property of Licensor.  Termination of Licensee's right to use the
Equipment Area under this Agreement will not affect Licensee's obligation to
make all License Fee payments coming due after the date of termination.  Upon
termination of Licensee's right to use the Equipment Area under this Agreement,
Licensor will have the right, but no obligation, to relicense the Equipment
Area to another party.  In the event the Equipment Area is licensed by Licensor
to another party, any License Fee received from the other party applicable to
the remainder of the Term will be applied first to any costs and expenses
incurred in attempting to enforce this Agreement or in relicensing the
Equipment Area, including costs of court and attorneys' fees with respect
thereto, and then to the satisfaction of Licensee's obligations under this
Agreement.  The remedies provided in this paragraph are cumulative and not to
the exclusion of any other rights or remedies that may be available to
Licensor, at law or in equity.  No waiver of any default or breach by Licensee
hereunder shall be construed to be a waiver or release of any other default or
breach of this Agreement at a later time.  No failure or delay by Licensor in
the exercise of any remedy provided for in this paragraph shall be construed as
a forfeiture or waiver of the same or any other remedy at a later time.





                                      F-8
<PAGE>   83
         19.     Miscellaneous.

                 (i)      Assignment.  Licensee shall have no right to assign,
sell or transfer its rights or obligations under this Agreement to any third
party without the prior written consent of Licensor, which consent may be
withheld by Licensor for any reason in its sole and absolute discretion.  Any
purported sale, transfer or assignment in violation of the provisions of this
paragraph shall be null and void and shall constitute an event of default
hereunder.  This Agreement and the rights of Licensor to any payments hereunder
are fully assignable by Licensor, and Licensee shall pay any such assignee
directly upon delivery of written notice of any such assignment to Licensee.

                 (ii)     Notices.  All notices, demands, payments and other
communications required to be given or made hereunder shall be in writing and
shall be hand-delivered or sent by nationally recognized overnight courier or
mailed by certified or registered mail, first class postage prepaid, to
Licensor at Suite 110, 3333 Lee Parkway, Dallas, Texas 75219, Attention:
Property Manager, with a copy to Crescent Real Estate Equities Limited
Partnership, 777 Main Street, Suite 2100, Fort Worth, Texas 76102, Attention:
James S. Wassel, or to Licensee at _____________________________________
___________________, _______________________, _____________________________ __,
Attention: __________________________________________, or to such other address
as Licensor or Licensee shall provide to each other in writing, provided that
no notice of either party's change of address shall be effective until fifteen
(15) days after the addressee's actual receipt thereof.  Notice shall be deemed
given upon tender of delivery (in the case of a hand-delivered notice) or upon
posting of same with the overnight courier or upon the depositing of same in an
official depository of the United States Postal Service (in the case of a
certified or registered letter).

                 (iii)    Entire Agreement.  This Agreement (including all
exhibits attached hereto, which are hereby incorporated by reference herein) is
the entire agreement between the parties concerning its subject matter, and it
supersedes and cancels all prior agreements or understandings, written or oral,
between the parties.

                 (iv)     Choice of Laws.  THIS AGREEMENT SHALL BE GOVERNED BY,
AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS
WITHOUT REGARD TO ANY OTHERWISE APPLICABLE PRINCIPLES OF CONFLICTS OF LAW.

                 (v)      No Lease.  The parties hereto acknowledge that this
Agreement is merely a license to use, and not an agreement to lease, the
Equipment Area.  This Agreement does not create any property rights or rights
of possession or occupancy whatsoever in favor of or on behalf of Licensee, but
only licenses to Licensee the right to use the Equipment Area for the purposes,
and in the manner, provided for in this Agreement.

                 (vi)     Binding Effect.  This Agreement shall be binding on
the successors, permitted assigns, heirs, executors and administrators of the
parties hereto.





                                      F-9
<PAGE>   84
                 (vii)    Amendments and Waiver.  This Agreement cannot be
changed or modified, and no breach hereof shall be deemed waived or released,
except in a writing executed by the party sought to be charged therewith.

                 (viii)   Late Charges and Interest.  Licensor may impose a
late payment charge equal to five percent (5%) of any amount due if not paid
within five (5) days from the date required to be paid hereunder.  In addition,
any payment due under this Agreement not paid within ten (10) days after the
date herein specified to be paid shall bear interest from the date such payment
is due to the date of actual payment at the rate of eighteen percent (18%) per
annum or the highest lawful rate of interest permitted by Texas or federal law,
whichever rate of interest is lower.

                 (ix)     Attorneys' Fees.  In the event either party is in
default beyond any applicable grace or notice period in the performance of any
of the terms of this Agreement and the other party employs an attorney in
connection therewith, the nonprevailing party agrees to pay the prevailing
party's reasonable attorneys' fees.

                 (x)      Interpretation.  Whenever the context shall require,
the singular shall include the plural, the plural shall include the singular
and words of any gender shall be deemed to include words of any other gender.
The captions contained in this Agreement are inserted only as a matter of
convenience and in no way define, limit, extend or describe the scope of this
Agreement or the intent of any provisions hereof.

                 (xi)     Severability.  In the event one or more of the
provisions of this Agreement are declared invalid, illegal or unenforceable in
any respect, such invalidity, illegality or unenforceability shall not affect
any other provisions hereof, and this Agreement shall be construed as if such
invalid, illegal or unenforceable provision had never been contained herein.

                 (xii)    No Personal Liability of Licensor.  If Licensor shall
fail to perform any covenant, term or condition of this Agreement and, as a
consequence, if Licensee shall recover a money judgment against Licensor, such
judgment shall be satisfied only out of the proceeds received at a judicial
sale upon execution and levy against the right, title and interest of Licensor
in the Building and in the rents or other income from the Building receivable
by Licensor, and neither Licensor nor Licensor's owners, partners, shareholders
or venturers shall have any personal, corporate or other liability hereunder.

                 (xiii)   Execution of Agreement.  The submission of this
Agreement for examination does not constitute a reservation of or option for
the Equipment Area or any other space within or on the Building and shall vest
no right in either party.  This Agreement shall become effective only after the
full execution and delivery hereof by all of the parties hereto and, if
required, upon the approval by the holder of any mortgage encumbering the
Project.





                                      F-10
<PAGE>   85
         IN WITNESS WHEREOF, Licensor and Licensee have caused this Agreement
to be duly executed as of the date first set forth above.


                            LICENSOR:                                         
                            --------                                          
                                                                              
                            CRESCENT REAL ESTATE EQUITIES LIMITED             
                            PARTNERSHIP, a Delaware limited partnership       
                                                                              
                            By:     Crescent Real Estate Equities, Ltd., a    
                                    Delaware corporation, its general partner 
                                                                              
                                                                              
                                    By:                                       
                                        ---------------------------------------
                                    Name:                                      
                                          -------------------------------------
                                    Title:                                     
                                          -------------------------------------
                                                                               
                                                                               
                            LICENSEE:                                          
                            --------                                           
                                                                               
                            PAGEMART WIRELESS, INC.,                           
                            a Delaware corporation                             
                                                                               
                                                                               
                            By:                                                
                                -----------------------------------------------
                            Name:                                              
                                  ---------------------------------------------
                            Title:                                             
                                  ---------------------------------------------





                                      F-11