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                                                               Exhibit 10.12 (f)






                                   AMENDMENT

         THIS AMENDMENT, dated as of March 30, 1999 ("Amendment"), between
UNION PACIFIC RESOURCES GROUP INC., a Utah corporation (the "Company"), and
KERRY R. BRITTAIN (the "Executive") amends the Agreement between the Company
and Executive entered into on March 18, 1999 (the "Agreement"). Defined terms
used herein shall have the meanings as set forth in the Agreement unless
otherwise defined herein.

1.       The Agreement is hereby amended to add a new Section 5.4 to read in
         its entirety as follows:

         Notwithstanding any provision herein or any provision in the Company's
         1995 Stock Option and Retention Stock Plan (or any agreement entered
         into thereunder) to the contrary (except any contrary provision
         dealing with a pooling of interests transaction), (A) upon a Change in
         Control, any Option then held by the Executive (other than an Option
         the exercisability of which is based exclusively on the attainment of
         performance targets which, at the time of the Change in Control, have
         not been met), shall be fully exercisable and any restriction on any
         Retention Share then held by the Executive (other than a Retention
         Share the vesting of which is based exclusively on the attainment of
         performance targets, which, at the time of the Change in Control, have
         not been met) shall lapse or be deemed fully satisfied, as applicable,
         and (B) if, following a Change in Control and during the term of this
         Agreement, the Executive is terminated by the Company for any reason
         other than Cause or the Executive terminates with Good Reason, then,
         with respect to any Option then held by the Executive, the Executive
         (or his Beneficiary, if applicable) shall have the right to exercise
         such Option at any time during the earlier of (i) the five-year period
         following such termination or (ii) the term of the Option; provided,
         however, that, with respect to any provision in (A) or (B) in this
         Section 5.4, if it is intended that the transaction constituting a
         Change in Control be accounted for as a pooling of interests under
         Accounting Principles Board Opinion No. 16 (or any successor thereto),
         and if the existence and/or operation of any such provision would
         violate Paragraph 47(c) thereof (or any successor thereto), then any
         such provision shall (in whole or in part to the minimum extent
         necessary to avoid a violation) be deemed null and void ab initio
         and/or any operation of such provision shall (in whole or in part to
         the minimum extent necessary to avoid a violation) be deemed to have
         no force or effect under law; provided further, however, that the
         foregoing proviso shall apply only if the transaction is otherwise
         eligible to be accounted for as a pooling of interests.



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         Except as amended hereby, all other terms and provisions shall remain
in full force and effect

         IN WITNESS WHEREOF, all parties hereto have executed this Amendment as
of the date and year first above written.

                                           UNION PACIFIC RESOURCE GROUP INC.




                                           By:
                                               --------------------------------
                                                          JACK L. MESSMAN



                                           EXECUTIVE




                                           By:

                                                          KERRY R. BRITTAIN