<PAGE>

                                  EXHIBIT 10.66


           PURCHASE AND SALE AGREEMENT FOR THE EXPERIAN/TRW BUILDINGS

<PAGE>

                           PURCHASE AND SALE AGREEMENT



                         ALLEN OFFICE INVESTMENT LIMITED
                               PARTNERSHIP, SELLER



                                       and




                           WELLS CAPITAL, INC., BUYER




<PAGE>

                                    INDEX TO

                           PURCHASE AND SALE AGREEMENT

<TABLE>
<S>                                                                          <C>
1.   Property Included in Sale ...........................................    1

2.   Purchase Price/Remedies .............................................    2

3.   Title to the Property ...............................................    3

4.   Buyer's Due Diligence ...............................................    3

5.   Buyer's Conditions to Closing .......................................    6

6.   Seller's Conditions to Closing ......................................    7

7.   The Closing .........................................................    8

8.   Representations and Warranties ......................................   11

9.   Condition of Property ...............................................   13

10.  Possession ..........................................................   15

11.  Tax-Deferred Exchange ...............................................   15

12.  Seller's Covenants ..................................................   15

13.  Miscellaneous .......................................................   16
</TABLE>

<PAGE>


EXHIBITS
--------

A        Legal
B        Existing Reports
C        Non-Foreign Certification
D        Notice to Tenant
E        Deed
F        Assignment and Assumption of Lessor's Interest in Leases
G        Bill of Sale
H        ADD General Assignment of Intangibles
I        Assignment and Assumption of Real Estate Purchase and Sale Agreement
J        Due Diligence Checklist
K        Credit Tenant Estoppel
L        Pending Litigation

<PAGE>

                           PURCHASE AND SALE AGREEMENT

     THIS PURCHASE AND SALE AGREEMENT (the "Agreement"), is made as of the 18th
day of March, 2002, (the "Agreement Date") by and between ALLEN OFFICE
INVESTMENT LIMITED PARTNERSHIP, a Texas limited partnership, herein referred to
as "Seller" and WELLS CAPITAL, INC., a Georgia corporation, herein referred to
as "Buyer."

                                R E C I T A L S:

     WHEREAS, Seller desires to sell certain improved real property along with
certain related personal and intangible property, and Buyer desires to purchase
said real, personal and intangible property on the terms and conditions set
forth herein;

     NOW, THEREFORE, in consideration of the foregoing and the mutual
undertakings set forth herein, and for good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged, the Buyer and Seller
hereby agree as follows:

     1.   Property Included in Sale. Seller hereby agrees to sell and convey to
Buyer, and Buyer hereby agrees to purchase from Seller, the following:

          (a) that certain tract or parcel of land located in Collin County,
Texas commonly known as 601 Experian Parkway, Allen, Texas, and more
particularly described in Exhibit A attached hereto (the "Land"), together with
Seller's interest in all rights, privileges and easements appurtenant to the
Land, including, without limitation, all minerals, oil, gas and other
hydrocarbon substances as well as all development rights, air rights, water,
water rights (and water stock, if any) relating to the Real Property and any
easements, rights-of-way or other appurtenances used in connection with the
beneficial use and enjoyment thereof (all such items, together with the Land,
the "Real Property");

          (b) The building(s) (if one or more than one, the "Building"), all
other improvements and fixtures located on the Real Property, and all apparatus,
equipment and appliances used in connection with the operation or occupancy of
the Real Property (except such apparatus, equipment and appliances owned by the
Credit Tenant under the Credit Lease (both defined below) (all of which are
collectively referred to as the "Improvements");

          (c) Any tangible or intangible personal property, if any, owned by
Seller and used in the ownership, use and operation of the Real Property and
Improvements (the "Personal Property");

          (d) all of Seller's rights under all permits and licenses, zoning
approvals, certificates of occupancy, warranties, lien waivers, contracts,
utility arrangements and other documents and agreements relating to the
development, construction, ownership, operation and occupancy of the Property
(collectively as the "Intangible Property"); and

<PAGE>

          (e)  any contract or lease rights, or other rights relating to the
ownership, use and operation of the Real Property including, but not limited to,
that certain Lease Agreement with Experian Information Solutions, Inc., an Ohio
corporation, successor-in-interest to TRW, Inc., an Ohio corporation ("Credit
Tenant") dated as of April 15, 1993, and Lease Amendment dated March 10, 1995,
and Assignment of Tenant's Interest in Lease (undated) (collectively, the
"Credit Lease").

          All of the items referred to in subparagraphs (a), (b), (c), (d) and
(e) above are hereinafter collectively referred to as the "Property."

     2.   Purchase Price/Remedies.

          (a)  The total purchase price (the "Purchase Price") for the Property
is Thirty-Five Million Three Hundred Fifty Thousand Dollars ($35,350,000.00).
The Purchase Price (subject to adjustments and prorations as contemplated
hereby) will be paid by wire transfer of immediately available funds in U.S.
dollars via the federal bank wire transfer system to First American Title
Insurance Company, Attn: Mary Lou Kennedy, 30 North LaSalle Street, Suite 310,
Chicago, Illinois 60602 (telephone: 312/917-7202; fax: 312/553-0480) (the "Title
Company") at Closing.

          (b)  Within three (3) business days of the Agreement Date, Buyer shall
deposit into escrow with the Title Company the sum of $350,000.00 as the earnest
money deposit (the "Deposit"). Any interest earned by the Deposit shall be
considered part of the Deposit. Except as otherwise provided in this Agreement,
the Deposit shall be held by the Title Company in a federally insured interest
bearing account and applied against the cash portion of the Purchase Price at
Closing or otherwise as specified in paragraphs 2(c) or (d) below, as
applicable.

          (c)  In the event Buyer should fail to consummate this Agreement for
any reason except Seller's default or the termination of this Agreement by Buyer
or Seller pursuant to a right to do so under the terms and provisions hereof,
then Seller, as its sole and exclusive remedy, may terminate this Agreement by
notifying Buyer thereof and receive the Deposit as liquidated damages and not as
a penalty. Buyer and Seller hereby agree that Seller will be damaged by the
failure of Buyer to consummate this Agreement except for the reasons stated
above. Therefore, Seller and Buyer hereby agree (i) that the Seller shall be
released from its obligations hereunder, except as otherwise provided in
paragraph 13(b), and the Deposit shall represent and be liquidated damages
payable to Seller in such event as a fair and reasonable sum to recompense
Seller in light of Seller's removal of the Property from the market and the
costs incurred, labor and services performed and the loss of its bargain, all of
which are difficult to ascertain and (ii) that such liquidated damages shall
constitute Seller's sole and exclusive remedy for a default by Buyer hereunder.
Upon any such termination, except as otherwise specifically provided in
paragraphs 4 and 13(b) hereof, neither Seller nor Buyer shall thereafter have
any further rights or obligations under this Agreement.

          (d)  In the event that Seller shall fail to consummate this Agreement
for any reason, except Buyer's default or a termination of this Agreement by
Buyer or Seller pursuant to a right to do so under the provisions hereof, Buyer,
as its sole remedy, may either (I) terminate this

                                       2

<PAGE>

Agreement and receive a refund of the Deposit and in the event of such
termination neither party shall have any further rights of obligation hereunder
except as otherwise specifically provided in paragraphs 4 and 13(b) hereof or
(ii) enforce an action against Seller for specific performance; provided that if
the remedy of specific performance is unavailable, then in addition to the
return of the Deposit to Buyer, Buyer shall also be entitled to receive
reimbursement of its out-of-pocket costs, as evidenced by appropriate supporting
documentation, not to exceed $50,000.00. Except as otherwise specifically
provided in the preceding sentence, Seller shall not be liable to Buyer for any
actual, punitive, speculative, consequential or other damages.

     3.   Title to the Property. At the Closing, Seller shall convey to Buyer
and Buyer shall accept marketable and insurable fee simple title to the Real
Property, all rights, privileges and easements appurtenant thereto, and to the
Improvements, by duly executed and acknowledged Special Warranty Deed in the
form attached hereto as Exhibit E (the "Deed"). Evidence of delivery of
insurable fee simple title shall be the issuance of a current TLTA Owner's
Policy of Title Insurance (the "Title Policy"), in the full amount of the
Purchase Price, in form and substance acceptable to Buyer in accordance
herewith, by the Title Company, insuring fee simple title to the Real Property,
Improvements, and appurtenant rights, privileges and easements, in the Buyer.

     4.   Buyer's Due Diligence. Buyer shall be allowed to conduct the following
due diligence prior to purchasing the Property:

          (a)  Buyer's review of title to the Property as shown on an existing
title policy and updated title commitment (the "Title Commitment") from the
Title Company, showing fee simple title to the Property in Seller and committing
to issue to Buyer the owner's title policy called for under paragraph 5(f) of
this Agreement, such Title Commitment to specify all easements, liens,
encumbrances, restrictions, conditions or covenants with respect to the
Property; and including copies of all documents referred to as exceptions to
title in the Title Commitment and an existing as-built survey showing the
location of all improvements and recorded easements on the Property (the
"Survey"), all of which shall be delivered by Seller with the other Due
Diligence Items. Within ten (10) business days after Buyer's receipt of the
Title Commitment and Survey (the "Title Documents"), Buyer may approve or
disapprove (in its sole and absolute discretion) the Title Documents for the
Property by delivering written notice to Seller ("Buyer's Title Notice")
specifying each title defect or matter for which Buyer is requesting a cure by
Seller ("Title Defect"). If Buyer fails to deliver Buyer's Title Notice to
Seller within the time period specified above, there shall be a conclusive
presumption that Buyer has disapproved the Title Documents and this Agreement
shall be terminated except as otherwise provided in paragraphs 4 and 13(b).
Within five (5) business days after receiving Buyer's Title Notice, Seller shall
deliver to Buyer written notice ("Seller's Title Notice") of those Title Defects
which Seller covenants and agrees to either eliminate or cure to Buyer's
satisfaction by the Closing Date. Seller's failure to deliver Seller's Title
Notice to Buyer within the time period specified above shall be deemed to
constitute Seller's election not to eliminate or cure any such Title Defect or
to satisfy any such Title Requirements. If Seller elects not to eliminate or
cure any Title Defects other than the Monetary Objections (which Seller shall be
obligated to cure and satisfy), the Buyer shall have the right, by written
notice delivered to Seller within five (5) business days of

                                       3

<PAGE>

Seller's Title Notice to either (i) waive its prior notice as to the Title
Defects which Seller has elected not to cure, or (ii) terminate this Agreement
as provided later in this section.

          Notwithstanding anything to the contrary contained in subsection
4(a)above, Seller shall be obligated to cure and/or satisfy or cause to be
deleted as an exception to title: (x) any of the following exceptions and
encumbrances to the title to the Property as may be disclosed by the Title
Commitment, all of which shall be referred to herein as "Monetary Objections":
any deed of trust, mortgage, or other security title, assignment of leases,
negative pledge, financing statement or similar security instrument encumbering
all or any portion of the Property put on the Property by Seller.

          Buyer shall order an updated Survey promptly upon execution of this
agreement. If the updated Survey is not delivered prior to the Approval Date,
then Buyer shall have an additional five (5) days after receipt of the updated
survey to provide Buyer's Title Notice and the Approval Date shall be extended
for this purpose solely as to the review of title and Survey, but not as to any
other Due Diligence Items.

          (b)  Buyer's review of the Credit Lease.

          (c)  Buyer's review of all environmental reports prepared for Seller
described in Exhibit B and any other environmental, engineering or structural
reports, if any, currently in the possession of Seller listed as in Exhibit J
hereto ("Existing Reports"). Seller is providing the Existing Reports to Buyer
for informational purposes only and Buyer shall not rely on such reports in
determining whether to purchase the Property. In the event the transaction
contemplated herein does not close for any reason whatsoever, Buyer shall
immediately return Existing Reports to Seller.

          (d)  existing surveys, plans and specifications of the Building or
other Improvements, in Seller's possession.

          (e)  copies of warranties for services and materials provided to the
Property, in Seller's possession.

          (f)  copies of licenses, permits, including, specifically, the
certificates of occupancy for the Building and Credit Tenant space, in Seller's
possession.

          (g)  a copy of the Ad Valorem Tax Abatement and the Sales Tax
Abatement and Joinder to the Ad Valorem Tax Abatement and the Sales Tax
Abatement identified as an "Operative Document" in the Tax Indemnity Agreement
attached as Exhibit C to the Assignment of Tenant's Interest in Lease (to the
Credit Lease) dated March 10, 1996.

          The items listed on Exhibit J and those items referred to above in
subparagraphs 4(a)-(g) and any other items provided by Seller to Buyer before or
after the Delivery Date as hereinafter defined, shall be collectively referred
to as the "Due Diligence Items." Seller agrees to provide the Due Diligence
Items on a date (the "Delivery Date") which is within five (5)

                                       4

<PAGE>

business days after the Agreement Date. Buyer acknowledges that the Credit
Lease, as amended, and the Environmental Indemnity were delivered prior to the
Agreement Date.

          (h)  Buyer's review of the physical and environmental characteristics
and condition of the Property. Subject to the terms of the Credit Lease, Seller
shall provide Buyer, its agents, representatives, consultants, contractors and
employees access to the Property following the Agreement Date for the purpose of
performing, at Buyer's sole cost and expense, non-invasive studies, physical
inspections, investigations and tests on the Property (the "Tests") provided
that no such tests shall be conducted without at least two (2) business days
prior written notice to Seller and as to any Tests which are invasive in nature,
Seller's prior written approval of such Tests. Buyer's access is further
conditioned on Buyer providing Seller with certificates of insurance listing
Seller as an additional insured on all applicable insurance policies evidencing
that Buyer's agents or contractors performing said Tests have insurance in types
and amounts satisfactory to Seller as determined by Seller in its reasonable
discretion. Limits shall be deemed reasonable if amounts are at least:

                    Type                              Limits

     Worker's Compensation Employer's Liability       $ Statutory

     General Liability                                $1,000,000/occurrence
                                                      $1,000,000/aggregate

     Automobile Liability                             $1,000,000/occurrence
                                                      $1,000,000/aggregate

     Professional Liability                           $1,000,000/occurrence
                                                      $1,000,000/aggregate

     Pollution Liability                              $1,000,000/occurrence
                                                      $1,000,000/aggregate

Buyer shall be required to conduct such Tests in a manner as to not unreasonably
disturb or interfere with the current use of the Property and upon completion of
such Tests, Buyer agrees at its sole cost to restore the Property to
substantially the condition it was in immediately prior to such Tests,
including, but not limited to the prompt removal of anything placed on the
Property in connection with such Tests.

BUYER SHALL INDEMNIFY, DEFEND (WITH COUNSEL REASONABLY SATISFACTORY TO SELLER),
PROTECT, AND HOLD SELLER HARMLESS FROM AND AGAINST ANY AND ALL LIABILITY, LOSS,
COST, DAMAGE, OR EXPENSE (INCLUDING, WITHOUT LIMITATION, REASONABLE ATTORNEYS'
FEES AND COSTS ACTUALLY INCURRED, BUT SPECIFICALLY EXCLUDING ANY CONSEQUENTIAL,
SPECIAL OR PUNITIVE DAMAGES) WHICH SELLER SUSTAINS OR INCURS BY REASON OF OR IN
CONNECTION WITH ANY TESTS

                                       5

<PAGE>

MADE BY BUYER OR BUYER'S AGENTS OR CONTRACTORS RELATING TO OR IN CONNECTION WITH
THE PROPERTY, OR ENTRIES BY BUYER OR ITS AGENTS OR CONTRACTORS ONTO THE
PROPERTY. Notwithstanding any provision to the contrary in this Agreement, the
aforesaid indemnity obligations of Buyer under this Agreement shall survive any
termination of this Agreement or any transfer pursuant to this Agreement for a
period of one year. Provided, however, Buyer shall not be liable for any losses
or liabilities resulting from Buyer's investigations uncovering the existence of
any environmental contamination or any other defects or conditions that
adversely impact the Property, except to the extent that Buyer's investigations
exacerbate such conditions.

          Seller agrees that in the event Buyer determines (such determination
to be made in Buyer's sole and absolute discretion) that the Property is not
suitable for its purposes, Buyer shall have the right to terminate this
Agreement by giving written notice thereof to Seller on or before 5:00 p.m.
Central Time on the date which is thirty (30) days following the later of (a)
the Agreement Date, or (b) the Delivery Date (the "Approval Date"). If Buyer
disapproves any of the Due Diligence Items or the physical and environmental
condition of the Property or otherwise determines in its sole discretion that
the Property is unsuitable for any reason, by providing Seller with written
notice, this Agreement shall terminate without any liability on the part of
either party, except as otherwise specifically provided in paragraphs 4 and
13(b) hereof. In the event of such termination, the Deposit shall be returned to
Buyer and thereafter, Buyer shall return to Seller all Due Diligence Items and
destroy any copies of same. If by 5:00 p.m. Central Time on the Approval Date
Buyer approves of the Due Diligence Items and the physical and environmental
condition of the Property by providing Seller with written notice, then this
Agreement shall remain in full force and effect (subject to the terms and
conditions hereof) and the Deposit shall be held and released by the Title
Company or credited against the Purchase Price as provided herein. If by 5:00
p.m. Central Time on the Approval Date Buyer does not waive or deem satisfied in
writing the Due Diligence Items and the physical and environmental condition of
the Property, there shall be a conclusive presumption that Buyer has approved
the Due Diligence Items and the physical and environmental condition of the
Property, this Agreement shall remain in full force and effect, and the Deposit
shall be held by the Title Company and credited to the Purchase Price or
otherwise released as provided herein.

  5.  Buyer's Conditions to Closing. The following conditions are conditions
precedent to Buyer's obligation to purchase the Property:

      (a) In the event that, prior to Closing, the Property, or any part
thereof, is destroyed or materially damaged, and such damage exceeds
$500,000.00, or if condemnation proceedings are commenced against the Property,
Buyer shall have the right, exercisable by giving notice of such decision to
Seller within ten (10) business days after receiving written notice of such
damage, destruction or condemnation proceedings, to terminate this Agreement, in
which case, the Deposit shall be returned to Buyer, and thereafter, the
Agreement shall terminate and neither party shall have any further rights or
obligations hereunder except as otherwise specifically provided in paragraphs 4
and 13(b) hereof. In the event the casualty damage to the Property is
$500,000.00 or less, Buyer shall accept the Property in its then condition and
proceed with the purchase with no reduction, offset or abatement of the Purchase
Price; provided that if Buyer

                                       6

<PAGE>

elects to accept the Property in its then condition (or is deemed to have
accepted the Property), all proceeds of insurance or condemnation awards paid or
payable to Seller by reason of such damage, destruction or condemnation shall be
paid or assigned to Buyer, together with the full amount of any deductible or if
the insurance is provided by self-insurance as provided in the Credit Lease,
Buyer shall receive such amount as would otherwise be available if third party
insurance coverage had been provided, subject to the rights of the Credit Tenant
to such proceeds or awards under the Credit Lease.

      (b) Seller shall have made all of the deliveries required to be made by
Seller as set forth in Section 7(b) hereof below.

      (c) Delivery by Seller on or before Closing of a Credit Tenant estoppel
certificate substantially in the form attached hereto and marked Exhibit K,
dated no earlier than thirty (30) days prior to the Closing Date.

      (d) Performance by Seller as and when required by this Agreement of
each and every term, covenant, condition and agreement required to be performed
by Seller pursuant to this Agreement prior to Closing.

      (e) Delivery of the Owner's Title Policy insuring marketable fee
simple title to the Buyer, in for and substance acceptable to Buyer without
exception accept as approved by Buyer in accordance with paragraph 4(a) hereof;

      (f) All of Seller's representations and warranties as set forth in
paragraph 8(a) below shall be true and correct and unmodified.

          In the event that the conditions set forth above in this paragraph 5
are not satisfied (and Buyer is not otherwise in default of this Agreement),
Buyer may elect to terminate this Agreement or waive satisfaction of the
condition and close escrow in either instance by giving written notice to
Seller. In the event of such termination, the Deposit shall be returned to Buyer
and thereafter the parties shall have no further rights or obligations hereunder
except as otherwise specifically provided in paragraphs 4 and 13(b) hereof;
provided that if the conditions are not satisfied as a result of a default by
Seller hereunder then Buyer shall be entitled to the remedies for a Seller's
default as set forth in Section 2(d) hereof.

  6.  Seller's Conditions to Closing.  The following conditions are conditions
precedent to Seller's obligation to sell the Property:

      (a) The approval of Seller's Investment Committee, which approval
Seller agrees to seek within twelve (12) business days after the Agreement Date.
If for any reason Seller's Investment Committee does not approve this Agreement
or the transaction contemplated herein, the Title Company shall return the
Deposit to Buyer, this Agreement shall terminate and thereafter neither party
shall have any further obligations or rights hereunder except as specifically
otherwise provided in paragraphs 4 and 13(b) hereof.

                                       7

<PAGE>

      (b) Delivery by Buyer at Closing of the Purchase Price (adjusted as
contemplated hereby) and the executed Assignment and Assumption of Leases in the
form attached hereto as Exhibit F.

      (c) Performance by Buyer as and when required by this Agreement of each
and every term, covenant, condition and agreement required to be performed by
Buyer pursuant to this Agreement prior to Closing.

          In the event that the conditions set forth in this paragraph 6 are not
satisfied (and Seller is not otherwise in default of this Agreement) Seller may
elect, at its sole discretion, to terminate this Agreement or waive satisfaction
of the condition and close escrow in either instance by written notice to Buyer.
In the event of such termination, for reasons described in (b) or (c) above, the
Deposit shall be retained by Seller and shall be non-refundable to the Buyer.
Also, in the event of any such termination, neither party hereto shall
thereafter have any further rights or obligations hereunder except as otherwise
specifically provided in paragraphs 4 and 13(b) hereof.

  7.  The Closing.

      (a) The Closing hereunder shall be held and delivery of all items to be
made at the Closing under the terms of this Agreement shall be made at the
offices of the Title Company within seven (7) business days after the Approval
Date, or such other date prior thereto as Buyer and Seller may mutually agree in
writing (the "Closing Date"). Such date may not be extended without the prior
written approval of both Seller and Buyer except that Seller, by giving Buyer
notice 48 hours before the Closing Date, shall have the unilateral right to
extend for a period not to exceed thirty (30) days, with prior written notice to
Buyer (as the same may be extended as provided in this paragraph 7(a)), to
obtain estoppels from the Credit Tenant or to cure any title defect or other
matter which would entitle Buyer to terminate this Agreement. In the event the
Closing does not occur on or before the Closing Date, the Title Company shall,
subject to the provisions of paragraph 2 with respect to the Deposit, and
subject to the applicable escrow closing letter, return to the depositor thereof
documents and instruments or funds which may have been deposited pursuant to
this Agreement. Any such return shall not, however, relieve either party hereto
of any liability it may have for its wrongful failure to close.

      (b) At or before the Closing, to be delivered at Closing, Seller
shall deliver to the Title Company into escrow the following:

          (i)  the Special Warranty Deed duly executed and acknowledged by
Seller, conveying title to the Property to Buyer in the form of Exhibit E as
required by paragraph 3 above;

          (ii) original or copy of the Credit Lease (and amendments thereto, if
any) in Seller's actual and physical possession, and a duly executed and
acknowledged Assignment and Assumption of Lease in the form attached hereto as
Exhibit F;

                                       8

<PAGE>

          (iii)  Seller's Non-Foreign Certification, duly executed and
acknowledged by Seller in the form attached as Exhibit C;

          (iv)   notice to Credit Tenant in the form attached as Exhibit D,
executed by Seller;

          (v)    Credit Tenant Estoppel Certificate in accordance with
subparagraph 5(c) hereof;

          (vi)   a Bill of Sale duly executed and acknowledged by Seller in the
form attached hereto as Exhibit G;

          (vii)  a General Assignment of Intangible Property and other
interests, duly executed and acknowledged by Seller, in the form attached hereto
as Exhibit H;

          (viii) any site plans and building drawings and specifications in the
possession of Seller;

          (ix)   Certificates of Occupancy, licenses, permits, guaranties, and
warranties relating to the ownership, operation or maintenance of the Property
in the possession of Seller (to the extent not previously been delivered);

          (x)    an affidavit of Seller as may be reasonably requested by the
Title Company to delete the standard exceptions and otherwise issue the Title
Policy as required hereby;

          (xi)   a certificate of Seller evidencing the reaffirmation of the
truth and accuracy of Seller's representations, warranties, and agreements as
set forth herein;

          (xii)  to the extent in Seller's possession, operating statements,
balance sheets and income and expense statements;

          (xiii) a settlement statement setting forth the amounts paid by or on
behalf of and/or credited to each of Buyer and Seller pursuant to this
Agreement; (a draft of which shall be prepared by Title Company and submitted to
the parties for approval at least five (5) business days prior to Closing);

          (xiv)  Such documentation as may reasonably be required by the Title
Company to establish that this Agreement, the transactions contemplated herein,
and the execution and delivery of the documents required hereunder, are duly
authorized, executed and delivered, including without limitation, a certified
copy of Seller's partnership certificate or other organizational documents of
any other entity comprising Seller or general partner of Seller, together with
all amendments and modifications thereof, of any partnership which is a Seller
or limited liability company which is a general partner of Seller, together with
duly executed and delivered consents and/or certificates of the partners or
members thereof, as applicable, with respect to the transactions contemplated by
this Agreement; and

                                       9

<PAGE>

          (xv)  any other documents, instruments or agreements called for
hereunder to be delivered by Seller which have not previously been delivered.

          Buyer may waive compliance on Seller's part under any of the foregoing
items by an instrument in writing.

      (c) At or before the Closing, Buyer shall deliver to escrow the
following: (i) the Purchase Price (as adjusted as contemplated hereby) and (ii)
any other documents, instruments or agreements called for hereunder to be
delivered by Buyer which have not previously been delivered.

      (d) Seller and Buyer shall each deposit such other instruments as are
reasonably required by the escrow holder to close the escrow and consummate the
purchase of the Property in accordance with the terms hereof.

      (e) The following income and expenses shall be apportioned or credited
with respect to the Property as of 12:01 on the Closing Date, with the portion
thereof allocable to periods beginning as of Closing shall be credited to Buyer,
or charged to Buyer, as applicable, and the portion thereof allocable to periods
ending as of Closing shall be credited to Seller, or charged to Seller, as
applicable, all of which prorations shall be made at Closing or, in the case of
allocations to be made after Closing, upon receipt of such payments or payment
of such expenses:

          (i)   Rents are payable in arrears on the 15th of each month. Rents
shall be prorated based on the actual number of days in the payment period for
the payment made during the month of Closing. (For example, the rent received
on February 15 is payment for occupancy from January 15 through February 14. If
the Closing would take place on the 14th of February, the Buyer would be
entitled to one day's rent with the balance going to the Seller. If the Closing
would take place on the 16th of February, the Seller would get the entire
payment made on February 15th and one day of rent from the March 15th payment,
with the balance of the March rent paid to the Buyer.)

      (f) The closing costs incurred in this transaction shall be allocated as
follows:

          (i)   Buyer shall pay the cost for any new Title Policy. Buyer shall
pay for any new or special endorsements to the Title Policy and any extended
coverage.

          (ii)  Buyer shall pay the cost of any transfer taxes and/or recording
fees applicable to the sale.

          (iii) Buyer shall pay the cost of any new or updated survey, phase I
environmental report, physical property condition report or appraisal required
by Buyer and any other Tests.

                                       10

<PAGE>

              (iv)   Buyer shall pay for all closing and escrow costs.

              (v)    Seller shall pay the Seller's Broker (as defined in
paragraph 13(b) of this Agreement) as set forth herein; and the costs to cure
any title defects and satisfy any Monetary Liens;

              (vi)   Buyer shall pay the Buyer's Broker (as defined in paragraph
13(b) of this Agreement) as set forth herein

              (vii)  Each party shall pay its own legal fees and expenses.

       8. Representations and Warranties.

          (a) Seller hereby represents and warrants to Buyer as follows:

              (i)    Seller is a limited partnership duly organized and validly
existing under the laws of the State of Texas and is in good standing under the
laws of the state in which the Property is located.

              (ii)   All closing documents executed by Seller which are to be
delivered to Buyer at the Closing are or at the Closing will be duly authorized,
executed, and delivered by Seller, are or at the Closing will be legal, valid,
and binding obligations of Seller, are sufficient to convey title, and do not
violate any provisions of any agreement to which Seller is a party or to which
it is subject.

              (iii)  Except as set forth on Exhibit L, there is no pending
litigation which materially affects the use and operation of the Property or
Seller's ability to fulfill all of its obligations under this Agreement.

              (iv)   Seller is the lessor or landlord or the successor lessor or
landlord under the Credit Lease. To the Seller's knowledge, except for the
Credit Lease, there are no other leases or occupancy agreements (written or
oral) affecting the Property.

              (v)    Seller has not received any written notification from any
governmental or public authority that the Property is in violation of any
applicable fire, health, building, use, occupancy or zoning laws where such
violation remains outstanding and, if unaddressed, would have a material adverse
effect on the use of the Property as currently owned and operated;

              (vi)   No condemnation, assessment or similar proceedings relating
to the Property are pending or to Seller's knowledge, threatened against the
Property and Seller has not received any written notice from any governmental or
quasi- governmental authority, agency or entity having jurisdiction over the
Property that the Property is presently the subject of any condemnation,
assessment or similar proceeding or charge;

                                       11

<PAGE>

       (vii)   Seller (A) is not in receivership or dissolution, (B) has not
admitted in writing its inability to pay its debts as they mature, (C) has not
been adjudicated a bankrupt, (D) has not filed a petition in voluntary
bankruptcy, a petition or answer seeking reorganization, or an arrangement with
creditors under the federal bankruptcy law, or any other similar law or statute
of the United States or any state, or (E) does not have any such petition
described in (D) filed against Seller; (F) is not a "foreign person" within the
meaning of Section 1445 of the Internal Revenue Code of 1986 (i.e., Seller is
not a non-resident alien, foreign corporation, foreign partnership, foreign
trust or foreign estate as those terms are defined in the Code and regulations
promulgated thereunder); and

       (viii)  Except for the Existing Reports, Seller has received no written
notification that there are any violations of environmental statutes, ordinances
or regulations affecting the Property or any environmental lien, charge, or
assessment. Except for the Existing Reports, no other environmental reports or
studies have been conducted by Seller with respect to the Property and no other
reports are in Seller's possession.

     The foregoing representations and warranties shall be in full force and
effect on the Agreement Date and at the Closing. Such representations and
warranties shall be deemed to have been reaffirmed and restated by Seller as of
the Closing Date, except for any material change in any of the foregoing
representations or warranties or any material breach thereof that occurs and
which is expressly disclosed by Seller to Buyer in writing at any time and from
time to time prior to the Closing (each a "Disclosure" and collectively, the
"Disclosures"), which Disclosures shall thereafter be updated by Seller prior to
the Closing Date. If any change in any of the foregoing representations or any
breach of any of the foregoing warranties or agreements is a material change or
breach, and Seller does not elect to cure such matters within twenty (20)
business days after Seller's receipt of a written request from Buyer to do so,
or does not agree in writing within said twenty (20) business day period to
indemnify Buyer against and hold Buyer harmless from any and all losses,
liabilities, claims, costs and expenses incurred by Buyer as a result thereof,
then, notwithstanding anything contained herein to the contrary, Buyer, at its
sole option, and as its sole remedy, may either (a) close and consummate the
transaction contemplated by this Agreement, without reduction in the Purchase
Price or (b) terminate this Agreement by written notice to Seller, whereupon the
Title Company shall return the Deposit to Buyer and the parties shall have no
rights or obligations hereunder, except for those which expressly survive any
such termination. Such election shall be made by Buyer within five (5) business
days after receipt of notice from Seller that Seller has elected not to cure or
indemnify Buyer with respect to such material change or breach. Failure of Buyer
to cause Seller to receive notice of such election of Buyer within such five (5)
business days period shall conclusively be construed as Buyer's having elected
alternative (a) above. The Closing Date shall be postponed automatically, if
necessary, to permit the full running of such thirty (30)-day period. The term
"Seller's Knowledge" as used herein means the actual knowledge (and not the
implied or constructive knowledge) without any duty of investigation or inquiry
of the following persons: Richard Jacavino, Equities Asset Manager; Tom Bell,
Equities Director; and Gary Lines, Equities Director, of Principal Capital Real
Estate Investors, LLC. All covenants, agreements, representations and warranties
made by Seller in this Agreement shall survive the Closing for no longer than
six (6) months and written notification of any claim arising therefrom must be

                                       12

<PAGE>

received in writing by Seller within such six (6) month period or such claim
shall be forever barred and Seller shall have no liability with respect thereto.
The aggregate liability of the Seller, with respect to all claims hereunder,
shall not exceed $250,000.00. Notwithstanding the foregoing, no representation,
warranty, covenant or agreement made in this Agreement by Seller shall survive
the Closing relative to any matters disclosed in the Due Diligence Items or
known to Buyer to be untrue or incorrect and of which Seller is not notified by
Buyer prior to or at the Closing. Buyer is deemed to have constructive knowledge
of all information contained in the Due Diligence Items that could be reasonably
inferred from such Due Diligence Items. Buyer further acknowledges it has a duty
of investigation and inquiry in determining whether or not the Property is
suitable for its purpose.

         (b) Buyer hereby represents and warrants to Seller as follows: (i)
Buyer is a corporation, duly organized and validly existing under the laws of
the State of Georgia and is in good standing under the laws of the State in
which the Property is located; (ii) all documents executed by Buyer which are to
be delivered to Seller at Closing are or at the Closing will be duly authorized,
executed, and delivered by Buyer, and are or at the Closing will be legal,
valid, and binding obligations of Buyer, and do not and at the Closing will not
violate any provisions of any agreement to which Buyer is a party or to which it
is subject; (iii) Buyer shall furnish all of the funds for the purchase of the
Property (other than funds supplied by institutional lenders which will hold
valid mortgage liens against the Property) and such funds will not be from
sources of funds or properties derived from any unlawful activity.

         (c) Seller and Buyer represent to each other that they are
sophisticated investors with substantial experience in investing in assets of
the same type as the Property and has such knowledge and experience in financial
and business matters that Buyer and Seller are capable of evaluating the merits
and risks of an investment in the Property.

     9.  Condition of Property. If Buyer does not terminate this Agreement on or
before the Approval Date, Buyer will have approved the physical and
environmental characteristics and condition of the Property, as well as the
economic characteristics of the Property and Buyer shall waive any and all
defects in the physical, environmental and economic characteristics and
condition of the Property. Buyer further acknowledges that neither Seller nor
any of Seller's officers or directors, nor Seller's employees, agents,
representatives, or any other person or entity acting on behalf of Seller
(hereafter, for the purpose of this paragraph, such persons and entities are
individually and collectively referred to as the "Seller"), except as otherwise
expressly provided in paragraph 8(a) herein or any of the closing documents to
be delivered by Seller, have made any representation, or warranties or
agreements (express or implied) by or on behalf of Seller as to any matters
concerning the Property, the economic results to be obtained or predicted, or
the present use thereof or the suitability for Buyer's intended use of the
Property, including, without limitation, the following: suitability of the
topography; the availability of water rights or utilities; the present and
future zoning, subdivision and any and all other land use matters; the condition
of the soil, subsoil, or groundwater; the purpose(s) to which the Property is
suited; drainage; flooding; access to public roads; or proposed routes of roads
or extensions thereof. Buyer acknowledges and agrees that the Property is to be
purchased, conveyed in its present condition, "as is" and that no patent or
latent defect in the physical or environmental

                                       13

<PAGE>

condition of the Property whether or not known or discovered, other than Buyer's
rights to terminate hereunder, shall affect the rights of either party hereto.
Except as otherwise provided herein or in any closing document to be delivered
by Seller at Closing, any documents furnished to Buyer by Seller relating to the
Property including, without limitation, rent rolls, service agreements,
management contracts, maps, surveys, studies, pro formas, reports and other
information, including but not limited to the Due Diligence Items, shall be
deemed furnished as a courtesy to Buyer but without warranty from Seller. All
work done, if any, by Buyer, in connection with preparing the Property for the
uses intended by Buyer including any and all fees, studies, reports, approvals,
plans, surveys, permits, and any expenses whatsoever necessary or desirable in
connection with Buyer's acquiring, developing, using and/or operating the
Property shall be obtained and paid for by, and shall be the sole responsibility
of Buyer. On or before the Approval Date, Buyer shall investigate any operative
or proposed governmental laws and regulations including land use laws and
regulations to which the Property may be subject and shall acquire the Property
upon the basis of its review and determination of the applicability and effect
of such laws and regulations. Buyer has neither received nor relied upon any
representations concerning such laws and regulations from Seller.

       EXCEPT FOR CLAIMS OF FRAUD OR WILLFUL MISREPRESENTATION ON THE PART OF
SELLER, AND EXCEPT FOR THOSE REPRESENTATIONS, WARRANTIES OR COVENANTS EXPRESSLY
SET FORTH HEREIN OR IN ANY CLOSING DOCUMENT TO BE DELIVERED BY SELLER AT
CLOSING, UPON CLOSING, BUYER, ON BEHALF OF ITSELF AND ITS EMPLOYEES, AGENTS,
SUCCESSORS AND ASSIGNS ATTORNEYS AND OTHER REPRESENTATIVES, AND EACH OF THEM,
HEREBY RELEASES SELLER FROM AND AGAINST ANY AND ALL CLAIMS, DEMANDS, CAUSES OF
ACTION, OBLIGATIONS, DAMAGES AND LIABILITIES OF ANY NATURE WHATSOEVER, WHETHER
ALLEGED UNDER ANY STATUTE, COMMON LAW OR OTHERWISE, DIRECTLY OR INDIRECTLY,
ARISING OUT OF OR RELATED TO THE CONDITION, OPERATION OR ECONOMIC PERFORMANCE OF
THE PROPERTY.

           By signing in the space provided below in this paragraph 9, Buyer
acknowledges that it has read and understood the provisions of this paragraph 9.

                                           Buyer:  WELLS CAPITAL, INC.,
                                                   a Georgia corporation

                                                   By:  /s/ Douglas P. Williams
                                                      --------------------------
                                                            Douglas P. Williams

                                                   Its: Senior Vice President
                                                        ------------------------

           BUYER ACKNOWLEDGES AND AGREES THAT, EXCEPT FOR THOSE REPRESENTATIONS,
WARRANTIES AND COVENANTS EXPRESSLY SET FORTH HEREIN OR IN ANY CLOSING DOCUMENT
TO BE DELIVERED BY SELLER AT CLOSING, TO THE MAXIMUM EXTENT PERMITTED BY LAW,
UPON CLOSING, THE SALE OF THE PROPERTY AS PROVIDED FOR HEREIN IS MADE ON AN "AS
IS" AND "WITH ALL FAULTS" CONDITION AND BASIS WITH ALL FAULTS AND

                                       14

<PAGE>

DEFECTS. IT IS UNDERSTOOD AND AGREED THAT, UPON CLOSING, IF BUYER ACCEPTS THE
PROPERTY, THE PURCHASE PRICE HAS BEEN ADJUSTED BY PRIOR NEGOTIATION TO REFLECT
THAT ALL THE PROPERTY IS SOLD BY SELLER AND PURCHASED BY BUYER SUBJECT TO THE
FOREGOING.

     10. Possession. Buyer shall have the right of possession (subject to the
rights of the Credit Tenant under the Credit Lease, as tenant only and without
rights or option to purchase the Property or any interest therein) on the
Closing Date, provided, however, that Seller shall allow authorized
representatives of Buyer reasonable access to the Property for the purposes of
satisfying Buyer with respect to satisfaction of any conditions precedent to the
Closing contained herein subject to the limitations set forth in subparagraph
4(e) hereof.

     11. Tax-Deferred Exchange. Buyer and Seller agree that, at either Buyer's
or Seller's sole election, this transaction shall be structured as an exchange
of like-kind properties under Section 1031 of the Internal Revenue Code of 1986,
as amended (the "Code"), and the regulations and proposed regulations
thereunder. The parties agree that if either wishes to make such election, it
must do so prior to the Closing Date. If either so elects, the other shall
reasonably cooperate, provided any such exchange is consummated pursuant to an
agreement that is mutually acceptable to Buyer and Seller and which shall be
executed and delivered on or before the Closing Date. The electing party shall
in all events be responsible for all costs and expenses related to the Section
1031 exchange and shall fully indemnify, defend and hold the other harmless from
and against any and all liability, claims, damages, expenses (including
reasonable attorneys' and paralegal fees and reasonable attorneys and paralegal
fees on appeal), proceedings and causes of action of any kind or nature
whatsoever arising out of, connected with or in any manner related to such 1031
exchange that would not have been incurred by the non-electing party if the
transaction were a purchase for cash. The provisions of the immediately
preceding sentence shall survive closing and the transfer of title to subject
Property to Buyer. Notwithstanding anything to the contrary contained in this
paragraph: (i) any such Section 1031 exchange shall be consummated through the
use of a facilitator or intermediary so that Buyer shall in no event be
requested or required to acquire title to any property other than the Property;
and, (ii) if the Buyer desires to do a reverse or parking 1031 exchange, such
exchange shall be done using the "exchange first technique" whereby the
relinquished property is conveyed to the facilitator or intermediary and the
replacement property is conveyed to the Buyer.

     12. Seller's Covenants.  Seller hereby covenants with Buyer as follows:

         (a) Seller shall use reasonable efforts to operate and maintain the
Property in a manner generally consistent with the manner in which Seller has
operated and maintained the Property prior to the date hereof.

         (b) Seller shall not amend, modify, extend or terminate the Credit
Lease without the Buyer's prior consent, not to be unreasonably withheld;
provided that Seller will obtain an estoppel in form and substance reasonably
satisfactory to Buyer as a condition of Closing.

                                       15

<PAGE>

          (c) Subject to receipt of the Deposit by the Title Company as provided
herein, Seller shall not accept offers or otherwise enter into any binding or
non-binding agreement for a purchase, financing or joint venture involving the
Property or any interest therein with any other person or entity and Seller
shall not dispose of, convey, assign or pledge any interest in the Property or
any interest therein or otherwise enter into any agreement affecting or
encumbering or agreeing to dispose of, convey, assign or pledge any interest the
Property or any interest therein, which agreement would be consummated prior to
or otherwise the survive the Closing. In addition, Seller hereby covenants and
agrees that, after the date of execution hereof and prior to the Closing, unless
consented to in writing by Buyer, Seller shall keep the terms of this Agreement
confidential and no press release or other public disclosure concerning this
Agreement shall be made by Seller.

     13.  Miscellaneous.

          (a) Notices. Any notice required or permitted to be given under this
Agreement shall be in writing and shall be effective upon receipt or refusal of
receipt and to the following addresses or facsimile numbers:

          If to Seller:

          ----------------------------------------------------------------------

             Allen Office Investment Limited Partnership
             c/o Principal Capital Management, LLC
             801 Grand Avenue
             Des Moines, Iowa 50392-1360
             Attn: Gary Lines
             Fax:  5015-248-8090
             Phone: 515-247-4858

          ----------------------------------------------------------------------


             With a copy to:

             Principal Capital Management, LLC
             c/o Closing Department
             801 Grand Avenue
             Des Moines, Iowa 50392-1360
             Attn:  Donise Cannaday
             Fax:   515-247-5926
             Phone: 515-248-0425

          ----------------------------------------------------------------------

                                       16

<PAGE>

          If to Buyer:

          ----------------------------------------------------------------------

             Wells Capital, Inc.              With a copy to:
             6200 The Corners Parkway
             Suite 250                        Alston & Bird, LLP
             Atlanta, GA 30092                One Atlantic Center
             Attn:  Michael C. Berndt         1201 West Peachtree St., Atlanta,
             Fax:   770-200-8510              GA 30309-3424
             Phone: 770-449-7800              Attn: Walter W. Mitchell
                                              Fax:   404-881-7777
                                              Phone: 404-881-7790

          ----------------------------------------------------------------------

or such other address as either party may from time to time specify in writing
to the other.

          (b) Brokers and Finders. Neither party has had any contact or dealings
regarding the Property, or any communication in connection with the subject
matter of this transaction, through any licensed real estate broker, entity,
agent, commission salesperson, or other person who will claim a right to
compensation or a commission or finder's fee as a procuring cause of the sale
contemplated herein, except that Seller has a separate agreement with Terrace
Associates, Inc., (the "Seller's Broker") for a total commission equal to .75%
of the Purchase Price, which shall be paid by Seller and Buyer has a separate
agreement with Capital Development (the "Buyer's Broker") for a total commission
equal to One Percent (1.00%) of the Purchase Price. In the event that any
company, firm, broker, agent, commission salesperson or finder (other than
Seller's Broker or Buyer's Broker, who shall respectively be paid by Seller and
Buyer as hereinabove provided) perfects a claim for a commission or finder's fee
based upon any such contract, dealings or communication, the party through whom
the company, firm, broker, agent, commission salesperson or finder makes his
claim shall indemnify the other party and be responsible for said commission or
fee and all costs and expenses (including reasonable attorneys' fees) or any
liability or damage incurred by the other party in defending against the same.
No commission shall be paid or become payable unless the Closing actually
occurs. The provisions of this subparagraph (b) shall survive Closing and any
termination, cancellation or rescission of this Agreement.

          (c) Successors and Assigns. This Agreement shall be binding upon, and
inure to the benefit of, the parties hereto and their respective successors,
heirs, administrators and assigns, and may be assigned by Buyer to an affiliated
entity provided that (i) Buyer shall remain jointly and severally liable for the
obligations contained in this agreement; (ii) Buyer and any assignee, by
accepting assignment of this Agreement, expressly agrees to defend and indemnify
Seller from any litigation arising out of the assignment; (iii) no further
assignment shall occur without the prior written consent of the Seller; (iv)
written notice of the assignment, including the name of the Assignee, is
provided to Seller no fewer than ten (10) business days prior to Closing; and
(v) Buyer shall provide to Seller at Closing an Assignment and Assumption of
Real Estate

                                       17

<PAGE>

Purchase and Sale Agreement in the form attached hereto as Exhibit I, executed
by both Buyer and Assignee.

          (d) Amendments. Except as otherwise provided herein, this Agreement
may be amended or modified by, and only by, a written instrument executed by
Seller and Buyer.

          (e) Governing Law. This Agreement shall be governed by and construed
in accordance with the laws of the state in which the Property is located.

          (f) Merger of Prior Agreements. This Agreement supersedes all prior
agreements and understandings between the parties hereto relating to the subject
matter hereof.

          (g) Enforcement. In the event either party hereto fails to perform any
of its obligations under this Agreement or in the event a dispute arises
concerning the meaning or interpretation of any provision of this Agreement, the
defaulting party or the party not prevailing in such dispute, as the case may
be, shall pay any and all costs and expenses incurred by the other party in
enforcing or establishing its rights hereunder, including, without limitation,
court costs and reasonable attorneys' fees. Buyer and Seller both acknowledge
each has been advised by counsel as to their respective rights, duties and
obligations in this Agreement and have had ample opportunity to negotiate same.
Thus, both Buyer and Seller acknowledge that any ambiguity in this Agreement
should not necessarily be resolved against the drafter of this Agreement.

          (h) Time of the Essence. Time is of the essence of this Agreement.

          (i) Counterparts. This Agreement may be executed in multiple
counterparts via facsimile, each of which shall be deemed to be an original, but
such counterparts when taken together shall constitute but one Agreement.

          (j) Survivability. Except as otherwise provided herein, the
representations, warranties and covenants contained in this Agreement shall
survive the closing of the purchase and sale and shall not be deemed merged in
any documentation delivered at the time of Closing, but shall remain in full
force and effect.

          (k) No Recordation. Neither Seller nor Buyer shall record this
Agreement or memorandum thereof in or among the land or chattel records of any
jurisdiction.

          (l) Proper Execution. The submission by Seller to Buyer of this
Agreement in unsigned form shall have no binding force and effect, shall not
constitute an option, and shall not confer any rights upon Buyer or Seller or
impose any obligations on Seller or Buyer irrespective of any reliance thereon,
change of position or partial performance until Seller and Buyer shall have both
executed this Agreement and the Deposit shall have been received by the Title
Company.

                                       18

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date first above written.

                               Seller:
                               ------

                            ALLEN OFFICE INVESTMENT LIMITED
                            PARTNERSHIP, a Texas limited partnership

                            By:      Equity FC, Ltd., an Iowa corporation,
                                     its General Partner

                                     By:  /s/ L. S. Valentine
                                        -----------------------------------
                                     Its:     L. S. Valentine
                                         ----------------------------------
                                              Counsel and Assistant Secretary

                                     By:  /s/ Thomas R. Pospisil
                                        -----------------------------------
                                     Its:     Thomas R. Pospisil
                                         ----------------------------------
                                              Counsel and Assistant Secretary


                               Buyer:
                               -----

                               WELLS CAPITAL, INC., a Georgia corporation


                               By: /s/ Douglas P. Williams
                                  -----------------------------------------
                               Its:    Douglas P. Williams
                                   ----------------------------------------
                                       Senior Vice President

                               Buyer's Social Security Number or Tax
                               Identification Number: 58 - 1565532
                                                     ----------------------

                                       19


<PAGE>


                                   EXHIBIT "A"

                                LEGAL DESCRIPTION

BEING all that tract of land in the City of Allen, Collin County, Texas, a part
of the MICHAEL SEE SURVEY, A-543, a part of the W. M. PERRIN SURVEY, A-708, a
part of the RUFUS SEWELL SURVEY, A-875, and being all LOT 1 and all of Lot 2,
Block 1 of the Replat of Enterprises Addition No. 1, an addition to the City of
Allen as recorded in Cabinet C, Page 567, Collin County Plat Records, and being
further described as follows:

BEGINNING at a 5/8 inch iron rod found at the northeast corner of said Lot 1,
said point being the intersection of the south line of Intecom Drive (a 50 foot
wide right-of-way) with the west line of Enterprise Boulevard (a 60 foot wide
right-of-way);

THENCE along the west line of Enterprise Boulevard as follows: South 11 degrees
30 minutes 00 seconds West, at 1136.98 feet passing a 5/8 inch iron rod found at
the southeast corner of said Lot 1 and the northeast corner of said Lot 2, in
all a total distance of 1439.21 feet to a 5/8 inch iron rod found for corner;
Southwesterly, 272.73 feet along a curve to the right which has a central angle
of 60 degrees 06 minutes 02 seconds, a radius of 260.00 feet, a tangent of
150.42 feet, and whose chord bears South 41 degrees 33 minutes 01 seconds West,
260.40 feet to a 58 inch iron rod found for corner; South 71 degrees 36 minutes
02 seconds West, 664.10 feet to a 5/8 inch iron rod found at the southwest
corner of said Lot 2, said point being in the east line of U.S. Highway No. 75
(a variable width right-of-way);

THENCE along the east line of U.S. Highway No. 75 as follows: North 14 degrees
03 minutes 05 seconds East, 120.00 feet to a 5/8 inch iron rod found for corner;
North 14 degrees 03 minutes 00 seconds East, at 720.30 feet passing a 5/8 inch
iron rod found at the northwest corner of said Lot 2 and the southwest corner of
said Lot 1, in all a total distance of 1801.00 feet to a 5/8 inch iron rod found
for corner; North 19 degrees 41 minutes 40 seconds East, 19.08 feet to a 5/8
inch iron rod found at the northwest corner of said Lot 1, said point being in
the south line of said Intecom Drive;

THENCE South 83 degrees 49 minutes 54 seconds East, 620.60 feet along the north
line of said Lot 1 and the south line of said Intecom Drive to the POINT OF
BEGINNING and containing 1,155,576 square feet or 26.528 acres of land.


<PAGE>

                                   EXHIBIT "B"

                                EXISTING REPORTS

..   Environmental - Building and Remedial Action Plan by Austin Commercial dated
    3/18/94; and
..   Asbestos - Asbestos Verification Inspection by Albert H. Halff Associates,
    Inc. dated 3/23/93.