<PAGE>
                                                                   Exhibit 10.15


                                                               February 12, 1999

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR INVESTMENT
AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR ANY STATE
SECURITIES LAWS.  SUCH SECURITIES MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE
OF SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER SAID ACT AND ANY APPLICABLE
STATE SECURITIES LAWS.

                           WARRANT TO PURCHASE UP TO
                        [  ] SHARES OF COMMON STOCK OF
                             GENOMICA CORPORATION
                        (Void after February 11, 2004)

          This Certifies that [    ] (the "Holder"), for value received, is
entitled to purchase from Genomica Corporation, a Delaware corporation (the
"Company"), having a place of business at 4001 Discovery Drive, Suite 130,
Boulder, Colorado 80303, up to a maximum of [ ]shares of fully paid and
nonassessable shares of the Company's Common Stock (the "Common Stock") at a
price of seventy-two cents ($0.72) per share (the "Stock Purchase Price"), at
any time or from time to time prior to the earlier of (i) up to and including
5:00 p.m. (Mountain Time) on February 11, 2004, (ii) upon the closing of the
Company's first firm commitment underwritten public offering of its Common Stock
registered under the Securities Act of 1933, as amended, or (iii) the closing of
an Acquisition or Asset Transfer (as such terms are defined below) (such earlier
date being referred to herein as the "Expiration Date"), upon surrender to the
Company at its principal office (or at such other location as the Company may
advise the Holder in writing) of this Warrant properly endorsed with the
Subscription Form (attached hereto as Exhibit A) and the Investment
                                      ---------
Representations Letter

(attached hereto as Exhibit B) duly filled in and signed and, if applicable,
                    ---------
upon payment in cash or by check of the aggregate Stock Purchase Price for the
number of shares for which this Warrant is being exercised determined in
accordance with the provisions hereof.  The Stock Purchase Price and the number
of shares purchasable hereunder are subject to adjustment as provided in Section
3 of this Warrant.  An "Acquisition" shall mean (A) any consolidation or merger
of the Company with or into any other corporation or other entity or person, or
any other corporate reorganization, in which the stockholders of the Company
immediately prior to such consolidation, merger or reorganization, hold less
than 50% of the outstanding voting power of the surviving entity (or its parent)
following the consolidation, merger or reorganization or (B) any transaction (or
series of related transactions involving a person or entity, or a group of
affiliated persons or entities) in which in excess of fifty percent (50%) of the
Company's outstanding voting power is transferred.  An "Asset Transfer" shall
mean a sale, lease or other disposition of all or substantially all of the
assets of the Company.

1.  Exercise; Issuance of Certificates; Payment for Shares.

          1.1  General.  This Warrant is exercisable at the option of the Holder
of record hereof, at any time or from time to time, commencing on the date
hereof up to the Expiration Date for all or any part of the shares of Common
Stock (but not for a fraction of a share) which may be purchased hereunder.

                                       1.
<PAGE>

          1.2  Issuance of Certificates.  The Company agrees that the shares of
Common Stock purchased under this Warrant shall be and are deemed to be issued
to the Holder hereof as the record owner of such shares as of the close of
business on the date on which this Warrant shall have been surrendered, properly
endorsed, the completed, executed Subscription Form (a copy of which is attached
hereto as Exhibit A) and Investment Representations Letter (a copy of which is
attached hereto as Exhibit B) delivered and payment (if any) made for such
shares.  Certificates for the shares of Common Stock so purchased, together with
any other securities or property to which the Holder hereof is entitled upon
such exercise, shall be delivered to the Holder hereof by the Company at the
Company's expense promptly after the rights represented by this Warrant have
been so exercised.  Each stock certificate so delivered shall be in such
denominations of Common Stock as may be requested by the Holder hereof and shall
be registered in the name of such Holder.  In case of a purchase of less than
all the shares which may be purchased under this Warrant, the Company shall
cancel this Warrant and execute and deliver a new Warrant or Warrants of like
tenor for the balance of the shares purchasable under the Warrant surrendered
upon such purchase to the Holder hereof within a reasonable time.

          1.3  Net Issue Exercise.  Notwithstanding any provisions herein to the
contrary, if the fair market value of one share of the Company's Common Stock is
greater than the Stock Purchase Price (at the date of calculation as set forth
below), in lieu of exercising this Warrant for cash, the Holder may elect to
receive shares equal to the value (as determined below) of this Warrant (or the
portion thereof being canceled) by surrender of this Warrant at the principal
office of the Company together with the properly endorsed Form of Subscription
and notice of such election in which event the Company shall issue to the Holder
a number of shares of Common Stock computed using the following formula:

               X = Y (A-B)
                   -------
                      A

       Where   X =  the number of shares of Common Stock to be issued to the
                    Holder

               Y =  the number of shares of Common Stock purchasable under the
                    Warrant or, if only a portion of the Warrant is being
                    exercised, the portion of the Warrant being canceled (at the
                    date of such calculation)

               A =  the fair market value of one share of the Company's Common
                    Stock (at the date of such calculation)

               B =  Stock Purchase Price (as adjusted to the date of such
                    calculation)

For purposes of the above calculation, the fair market value of one share of
Common Stock shall be determined by the Company's Board of Directors in good
faith; provided, however, that in the event the Company makes an initial public
offering of its Common Stock the fair market value per share shall be:  (i) if
the Warrant is being converted in connection with and contingent upon a public
offering of the Company's securities, and if the Company's registration
statement relating to such public offering has been declared effective by the
U.S. Securities and Exchange Commission, then the fair market value of the
Common Stock shall be the initial "Price to Public" specified in the final
prospectus; or (ii) if the Warrant is not being converted in

                                       2.
<PAGE>

connection with and contingent upon a public offering of the Company's
securities, then as follows: (x) if traded on a securities exchange, the Nasdaq
National Market or the Nasdaq SmallCap Market, the fair market value of the
Common Stock shall be deemed to be the average of the closing or last reported
sale prices of the Common Stock on such exchange or market over the 30-day
period ending five business days prior to the date of calculation or (y) if
otherwise traded in an over-the-counter market, the fair market value of the
Common Stock shall be deemed to be the median of the average of the reported
closing bid and ask prices of the Common Stock over the 30-day period ending
five business days prior to the date of calculation.

2.   Shares to be Fully Paid; Reservation of Shares.  The Company covenants and
agrees that all shares of Common Stock that may be issued upon the exercise of
the rights represented by this Warrant will, upon issuance, be duly authorized,
validly issued, fully paid and non-assessable and free from all preemptive
rights of any stockholder and free of all taxes, liens and charges with respect
to the issue thereof.  The Company further covenants and agrees that, during the
period within which the rights represented by this Warrant may be exercised, the
Company will at all times have authorized and reserved, for the purpose of issue
or transfer upon exercise of the subscription rights evidenced by this Warrant,
a sufficient number of shares of authorized but unissued Common Stock, or other
securities and property, when and as required to provide for the exercise of the
rights represented by this Warrant.  The Company will take all such action as
may be necessary to assure that such shares of Common Stock may be issued as
provided herein without violation of any applicable law or regulation, or of any
requirements of any domestic securities exchange upon which the Common Stock may
be listed; provided, however, that the Company shall not be required to effect a
registration under federal or state securities laws with respect to such
exercise.

3.   Adjustment of Stock Purchase Price and Number of Shares.  The Stock
Purchase Price and the number of shares purchasable upon the exercise of this
Warrant shall be subject to adjustment from time to time upon the occurrence of
certain events described in this Section 3.  Upon each adjustment of the Stock
Purchase Price, the Holder of this Warrant shall thereafter be entitled to
purchase, at the Stock Purchase Price resulting from such adjustment, the number
of shares obtained by multiplying the Stock Purchase Price in effect immediately
prior to such adjustment by the number of shares purchasable pursuant hereto
immediately prior to such adjustment, and dividing the product thereof by the
Stock Purchase Price resulting from such adjustment.

     3.1  Subdivision or Combination of Stock. In case the Company shall at any
time subdivide its outstanding shares of Common Stock into a greater number of
shares, the Stock Purchase Price in effect immediately prior to such subdivision
shall be proportionately reduced, and conversely, in case the outstanding shares
of Common Stock of the Company shall be combined into a smaller number of
shares, the Stock Purchase Price in effect immediately prior to such combination
shall be proportionately increased.

     3.2  Dividends in Common Stock, Other Stock, Property, Reclassification. If
at any time or from time to time the holders of Common Stock (or any shares of
stock or other securities at the time receivable upon the exercise of this
Warrant) shall have received or become entitled to receive, without payment
therefor,

                                       3.
<PAGE>

          3.2.1  Common Stock or any shares of stock or other securities which
are at any time directly or indirectly convertible into or exchangeable for
Common Stock, or any rights or options to subscribe for, purchase or otherwise
acquire any of the foregoing by way of dividend or other distribution;

          3.2.2  Any cash paid or payable otherwise than as a cash dividend; or

          3.2.3  Common Stock or additional stock or other securities or
property (including cash) by way of spin-off, split-up, reclassification,
combination of shares or similar corporate rearrangement (other than (i) shares
of Common Stock issued as a stock split, adjustments in respect of which shall
be covered by the terms of Section 3.1 above or (ii) an event for which
adjustment is otherwise made pursuant to Section 3.3 below);

then and in each such case, the Holder hereof shall, upon the exercise of this
Warrant, be entitled to receive, in addition to the number of shares of Common
Stock receivable thereupon, and without payment of any additional consideration
therefor, the amount of stock and other securities and property (including cash
in the cases referred to in clauses 3.2.2 and 3.2.3 above) which such Holder
would hold on the date of such exercise had it been the Holder of record of such
Common Stock as of the date on which holders of Common Stock received or became
entitled to receive such shares or all other additional stock and other
securities and property.

     3.3  Reorganization, Reclassification, Consolidation, Merger or Sale.  If
at any time while this Warrant, or any portion thereof, is outstanding and
unexpired, there shall be any capital reorganization of the capital stock of the
Company, or any consolidation or merger of the Company with another corporation,
or the sale of all or substantially all of its assets to another corporation not
involving an Asset Transfer or Acquisition and effected in such a way that
holders of Common Stock shall be entitled to receive stock, securities, or other
assets or property, then lawful and adequate provisions shall be made to entitle
the Holder hereof to receive, upon exercise of this Warrant (in lieu of the
shares of the Common Stock of the Company immediately theretofore purchasable
and receivable upon the exercise of the rights represented hereby) such shares
of stock, securities or other assets or property as may be issued or payable
with respect to or in exchange for a number of outstanding shares of such Common
Stock equal to the number of shares of such stock immediately theretofore
purchasable and receivable upon the exercise of the rights represented hereby;
provided, however, that in the event the value of the stock, securities or other
assets or property (determined in good faith by the Board of Directors of the
Company) issuable or payable with respect to one share of the Common Stock of
the Company immediately theretofore purchasable and receivable upon the exercise
of the rights represented hereby is in excess of the Stock Purchase Price hereof
effective at the time of the reorganization, reclassification, consolidation,
merger or sale and the resale of securities received in such reorganization,
reclassification, consolidation, merger or sale, if any, is registered so that
such securities may be immediately resold, then this Warrant shall expire unless
exercised prior to such reorganization, reclassification, consolidation, merger
or sale.  In any reorganization, reclassification, consolidation, merger or sale
described above in which the Warrant does not terminate appropriate provision
shall be made with respect to the rights and interests of the Holder of this
Warrant to the end that the provisions hereof (including, without limitation,
provisions for adjustments of the Stock Purchase Price and of the number of
shares purchasable and receivable upon the exercise of this Warrant) shall
thereafter be applicable, as

                                       4.
<PAGE>

nearly as may be, in relation to any shares of stock, securities or assets of
the surviving corporation or its parent thereafter deliverable upon the exercise
hereof. The Company will not effect any such consolidation, merger or sale
unless, prior to the consummation thereof, the successor corporation (if other
than the Company) or such corporation's parent resulting from such consolidation
or the corporation purchasing such assets shall assume by written instrument,
executed and mailed or delivered to the registered Holder hereof at the last
address of such Holder appearing on the books of the Company, the obligation to
deliver to such Holder such shares of stock, securities or assets as, in
accordance with the foregoing provisions, such Holder may be entitled to
purchase.

     3.4  Notice of Adjustment.  Upon any adjustment of the Stock Purchase Price
or any increase or decrease in the number of shares purchasable upon the
exercise of this Warrant, the Company shall give written notice thereof, by
certified mail, postage prepaid, or by reputable overnight courier, addressed to
the registered Holder of this Warrant at the address of such Holder as shown on
the books of the Company.  The notice shall be signed by an officer of the
Company and shall state the Stock Purchase Price resulting from such adjustment
and the increase or decrease, if any, in the number of shares purchasable at
such price upon the exercise of this Warrant, setting forth in reasonable detail
the method of calculation and the facts upon which such calculation is based.

     3.5  Other Notices.  If at any time:

          3.5.1  the Company shall declare any cash dividend upon its Common
Stock;

          3.5.2  the Company shall declare any dividend upon its Common Stock
payable in stock or make any special dividend or other distribution to the
holders of its Common Stock;

          3.5.3  there shall be any capital reorganization or reclassification
of the capital stock of the Company; any Asset Transfer or Acquisition or any
other consolidation or merger of the Company with, or sale of all or
substantially all of its assets to, another corporation;

          3.5.4  there shall be a voluntary or involuntary dissolution,
liquidation or winding-up of the Company; or

          3.5.5  there shall be an initial public offering of securities of the
Company;

then, in any one or more of said cases, the Company shall give, by first class
mail, postage prepaid, addressed to the Holder of this Warrant at the address of
such Holder as shown on the books of the Company, (a) at least ten (10) days
prior written notice of the date on which the books of the Company shall close
or a record shall be taken for such dividend, distribution or subscription
rights or for determining rights to vote in respect of any such reorganization,
reclassification, consolidation, merger, sale, dissolution, liquidation or
winding-up and (b) in the case of any such reorganization, reclassification,
consolidation, merger, sale, dissolution, liquidation, winding-up or public
offering, at least twenty (20) days prior written notice of the date when the
same shall take place; provided, however, that the Holder shall make reasonable
efforts attempt to respond to such notice as early as possible after the receipt
thereof.  Any notice given in accordance with the foregoing clause (a) shall
also specify, in the case of any such dividend, distribution or subscription
rights, the date on which the holder of Common Stock shall

                                       5.
<PAGE>

be entitled thereto. Any notice given in accordance with the foregoing clause
(b) shall also specify the date on which the holder of Common Stock shall be
entitled to exchange their Common Stock for securities or other property
deliverable upon such reorganization, reclassification, consolidation, merger,
sale, dissolution, liquidation or winding-up, as the case may be.

     3.6  Certain Events.  If any change in the outstanding Common Stock of the
Company or any other event occurs as to which the other provisions of this
Section 3 are not strictly applicable or if strictly applicable would not fairly
protect the purchase rights of the Holder of the Warrant in accordance with such
provisions, the Board of Directors of the Company shall make an adjustment in
the number and class of shares available under the Warrant, the Stock Purchase
Price or the application of such provisions, so as to protect such purchase
rights as aforesaid.  The adjustment shall be such as will give the Holder of
the Warrant upon exercise for the same aggregate Stock Purchase Price the total
number, class and kind of shares as he would have owned had the Warrant been
exercised prior to the event and had he continued to hold such shares until
after the event requiring adjustment.

4.   Issue Tax.  The issuance of certificates for shares of Common Stock upon
the exercise of the Warrant shall be made without charge to the Holder of the
Warrant for any issue tax in respect thereof; provided, however, that the
Company shall not be required to pay any tax which may be payable in respect of
any transfer involved in the issuance and delivery of any certificate in a name
other than that of the then Holder of the Warrant being exercised.

5.   Closing of Books.  The Company will at no time close its transfer books
against the transfer of any warrant or of any shares of Common Stock issued or
issuable upon the exercise of any warrant in any manner which interferes with
the timely exercise of this Warrant.

6.   No Voting or Dividend Rights; Limitation of Liability.  Nothing contained
in this Warrant shall be construed as conferring upon the Holder hereof the
right to vote or to consent or to receive notice as a stockholder of the Company
or any other matters or any rights whatsoever as a stockholder of the Company.
Except as provided herein, no dividends or interest shall be payable or accrued
in respect of this Warrant or the interest represented hereby or the shares
purchasable hereunder until, and only to the extent that, this Warrant shall
have been exercised.  No provision hereof in the absence of affirmative action
by the Holder to purchase shares of Common Stock, and no mere enumeration herein
of the rights or privileges of the Holder hereof, shall give rise to any
liability of such Holder for the Stock Purchase Price or as a stockholder of the
Company, whether such liability is asserted by the Company or by its creditors.

7.   Warrants Transferable.  Subject to compliance with the provisions of
applicable federal and state securities laws, this Warrant and all rights
hereunder are transferable, in whole or in part, without charge to the Holder
hereof (except for transfer taxes), upon surrender of this Warrant properly
endorsed and in compliance with such laws.  Each taker and Holder of this
Warrant, by taking or holding the same, consents and agrees that this Warrant,
when endorsed in blank, shall be deemed negotiable, and that the transferee,
when this Warrant shall have been so endorsed, may be treated by the Company, at
the Company's option, and all other persons dealing with this Warrant as the
absolute owner hereof for any purpose and as the person entitled to exercise the
rights represented by this Warrant, or to the transfer hereof on the books of
the

                                       6.
<PAGE>

Company, any notice to the contrary notwithstanding; but until such transfer on
such books, the Company may treat the registered owner hereof as the owner for
all purposes. Upon any such transfer, all references in this Warrant to the
"Holder" shall be deemed to refer to the transferee of this Warrant.

8.   Modification and Waiver.  Any change, waiver, discharge or termination
agreed to in writing by a majority in interest of Holders of Warrants of the
Company of even date (determined by reference to the number of shares underlying
such Warrants) shall be binding on the Holder and the Holder's assigns.

9.   Notices.  Any notice, request or other document required or permitted to be
given or delivered to the Holder hereof or the Company shall be delivered or
shall be sent by certified mail, postage prepaid, to each such Holder at its
address as shown on the books of the Company or to the Company at the address
indicated therefor in the first paragraph of this Warrant or such other address
as either may from time to time provide to the other and shall be deemed to be
received upon delivery or four (4) business days after deposit in the U.S. mail.

10.  Descriptive Headings and Governing Law.  The description headings of the
several sections and paragraphs of this Warrant are inserted for convenience
only and do not constitute a part of this Warrant.  This Warrant shall be
construed and enforced in accordance with, and the rights of the parties shall
be governed by, the laws of the State of Colorado.

11.  Lost Warrants.  The Company represents and warrants to the Holder hereof
that upon receipt of evidence reasonably satisfactory to the Company of the
loss, theft, destruction, or mutilation of this Warrant and, in the case of any
such loss, theft or destruction, upon receipt of an indemnity reasonably
satisfactory to the Company, or in the case of any such mutilation upon
surrender and cancellation of such Warrant, the Company, at its expense, will
make and deliver a new Warrant, of like tenor, in lieu of the lost, stolen,
destroyed or mutilated Warrant.

12.  Fractional Shares.  No fractional shares shall be issued upon exercise of
this Warrant.  The Company shall, in lieu of issuing any fractional share, pay
the Holder entitled to such fraction a sum in cash equal to such fraction
multiplied by the then effective Stock Purchase Price.

13.  Binding Effect on Successors.  This Warrant shall be binding upon any
corporation succeeding the Company by merger, consolidation or acquisition of
all or substantially all of the Company's assets.  All of the obligations of the
Company relating to the Common Stock issuable upon the exercise of this Warrant
shall survive the exercise and termination of this Warrant.  All of the
covenants and agreements of the Company shall inure to the benefit of the
successors and assigns of the holder hereof.

14.  Rights of Common Stock.  Upon the exercise of this Warrant into shares of
Common Stock, the Company shall grant, and ensure that the Holder is given,
identical rights with respect to such shares of Common Stock as those granted to
the holders of the then outstanding Common Stock who hold like amounts of Common
Stock.  For purposes of this Section, all shares of Common Stock owned by Holder
shall be aggregated.

                                       7.
<PAGE>

15.  Registration Rights.  Upon the exercise of this Warrant into shares of
Common Stock, the Holder shall be entitled to those piggyback registration
rights set forth in Section 3.2 of that certain Investors' Rights Agreement, by
and among the Company and the parties named therein, dated as of February 12,
1999 (the "Investors' Rights Agreement"), and the shares of Common Stock issued
upon exercise of this Warrant shall be deemed to be Registrable Securities (as
such term is defined in Section 1.2 of the Investors' Rights Agreement) for the
purposes of Section 3.2 thereunder.

                                       8.
<PAGE>

     In Witness Whereof, the Company has caused this Warrant as of the date
first set forth above.

                                        Genomica Corporation,
                                        a Delaware corporation


                                        _________________________________
                                        Thomas G. Marr
                                        President

                                       9.
<PAGE>

                                   Exhibit A

                               SUBSCRIPTION FORM

                                                      Date:______________, 19___

Genomica Corporation
4001 Discovery Drive
Suite 130
Boulder, CO 80303
Attn: President

Ladies and Gentlemen:

[_]  The undersigned hereby elects to exercise the warrant issued to it by
     Genomica Corporation (the "Company") and dated February 12, 1999, (the
     "Warrant") and to purchase thereunder ______________________________ shares
     of the Common Stock of the Company (the "Shares") at a purchase price of
     seventy-two cents ($0.72) per Share, or an aggregate purchase price of
     ___________________________________ ($__________) (the "Purchase Price").

[_]  The undersigned hereby elects to convert ___________________ percent (___%)
     of the value of the Warrant pursuant to the provisions of Section 1.3 of
     the Warrant.

     Pursuant to the terms of the Warrant the undersigned has delivered the
Purchase Price herewith in full in cash or by certified check or wire transfer
or under the net exercise provision.  The undersigned also makes the
representations set forth on the attached Exhibit B of the Warrant.

                                   Very truly yours,

                                   ____________________________________

                                   By:_________________________________

                                   Title:______________________________
<PAGE>

                                   Exhibit B

                          INVESTMENT REPRESENTATIONS

THIS AGREEMENT MUST BE COMPLETED, SIGNED AND RETURNED TO GENOMICA CORPORATION
ALONG WITH THE SUBSCRIPTION FORM BEFORE THE COMMON STOCK ISSUABLE UPON EXERCISE
OF THE WARRANT DATED FEBRUARY 12, 1999, WILL BE ISSUED.

                                                     _____________________, 19__

Genomica Corporation
4001 Discovery Drive
Suite 130
Boulder, Colorado 80303
Attn: President

Ladies and Gentlemen:

     The undersigned, [_________________________] ("Purchaser"), intends to
acquire up to __________________________ shares of the Common Stock of Genomica
Corporation (the "Company") pursuant to the exercise or conversion of the
warrant to purchase such Common Stock held by the Purchaser (the "Warrant").
The Common Stock will be issued to Purchaser in a transaction not involving a
public offering and pursuant to an exemption from registration under the
Securities Act of 1933, as amended (the "1933 Act") and applicable state
securities laws.  Purchaser has been advised that the Common Stock has not been
registered under the 1933 Act or state securities laws on the ground that this
transaction is exempt from registration, and that reliance by the Company on
such exemptions is predicated in part on Purchaser's representations set forth
in this letter.  Accordingly, Purchaser represents, warrants and agrees as
follows:

     1.   Purchaser is acquiring the Common Stock for its own account and
     beneficial interest, to hold for investment and not for sale or with a view
     to distribution of the Common Stock or any part thereof. Purchaser has no
     present intention of selling (in connection with a distribution or
     otherwise), granting any participation in, or otherwise distributing the
     same, and does not presently have reason to anticipate a change in such
     intention.

     2.   Purchaser acknowledges that it has received all the information it has
     requested from the Company and considers necessary or appropriate for
     deciding whether to acquire the Common Stock.  Purchaser represents that it
     has had an opportunity to ask questions and receive answers from the
     Company regarding the terms and conditions of the offering of the Common
     Stock and to obtain any additional information necessary to verify the
     accuracy of the information given the Purchaser.  Purchaser further
     represents that it has such knowledge and experience in financial and
     business matters that it is capable of evaluating the merits and risk of
     this investment.

     3.   Purchaser is an "accredited investor" as such term is defined in Rule
     501 under the 1933 Act.

                                      2.
<PAGE>

     4.   Purchaser acknowledges that investment in the Common Stock involves a
     high degree of risk, and represents that it is able, without materially
     impairing its financial condition, to hold the Common Stock for an
     indefinite period of time and to suffer a complete loss of its investment.

     5.   Purchaser has been informed that under the 1933 Act, the Common Stock
     must be held indefinitely unless it is subsequently registered under the
     1933 Act or unless an exemption from such registration (such as Rule 144)
     is available with respect to any proposed transfer or disposition by
     Purchaser of the Common Stock. Purchaser further agrees that the Company
     may refuse to permit Purchaser to sell, transfer or dispose of the Common
     Stock (except as permitted under Rule 144) unless there is in effect a
     registration statement under the 1933 Act and any applicable state
     securities laws covering such transfer, or unless, if reasonably required,
     Purchaser furnishes an opinion of counsel reasonably satisfactory to
     counsel for the Company, to the effect that such registration is not
     required. Purchaser shall not make any sale, transfer or other disposition
     of the Common Stock in violation of the 1933 Act or the General Rules and
     Regulations promulgated thereunder by the Securities and Exchange
     Commission or in violation of any applicable state securities law.

     6.   Purchaser also understands and agrees that there will be placed on the
     certificate(s) for the Common Stock, or any substitutions therefor, a
     legend stating in substance:

     "The shares represented by this certificate have not been registered under
     the Securities Act of 1933, as amended (the "1933 Act"), or any state
     securities laws. These shares have been acquired for investment and may not
     be sold or otherwise transferred in the absence of an effective
     registration statement for these shares under the 1933 Act and applicable
     state securities laws, or, if reasonably required, an opinion of counsel
     satisfactory to the Company that registration is not required and that an
     applicable exemption is available."

     Purchaser has carefully read this letter and has discussed its requirements
and other applicable limitations upon Purchaser's resale of the Common Stock
with Purchaser's counsel.

                              Very truly yours,

                              __________________________________

                              By:_______________________________

                              Title:____________________________

                                      3.
<PAGE>

                        Warrant Agreements Common Stock
                        -------------------------------

                             Supplemental Schedule
                             ---------------------

The following investor executed Warrant Agreements to purchase Common Stock:

Investor                            Number of Shares            Date
--------                            ----------------      -----------------

Punk, Ziegel & Company              54,166                December 16, 1998

Punk, Ziegel & Company              604,166               February 12, 1999