<PAGE>
 

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  CUSIP NO. 989070R17                   13D                PAGE 2 OF 7 PAGES
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      NAME OF REPORTING PERSON
 1    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Peter M. Holt       
      S.S. No. 451-80-6094
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      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
 2                                                              (a) [_]
                                                                (b) [_]
                                                 
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      SEC USE ONLY
 3
 

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      SOURCE OF FUNDS
 4    
           PF

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      CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
 5    ITEMS 2(d) or 2(e)
                                                                    [_]

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      CITIZENSHIP OR PLACE OF ORGANIZATION
 6
           United States of America

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                          SOLE VOTING POWER
                     7     7,572,146*       *Not adjusted for 1:5 reverse  
     NUMBER OF                               stock split approved by Zapata
                                             shareholders on April 27, 1994
      SHARES       -----------------------------------------------------------
                          SHARED VOTING POWER
   BENEFICIALLY      8     4,602,875*
                          
     OWNED BY
                   -----------------------------------------------------------
       EACH               SOLE DISPOSITIVE POWER
                     9     7,572,146*
    REPORTING             
 
      PERSON       -----------------------------------------------------------
                          SHARED DISPOSITIVE POWER
       WITH          10    4,602,875*
                          
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      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
11     13,175,021*
      

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      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
12                                                                  [_]
                                
 
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      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
13     8.3
      

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      TYPE OF REPORTING PERSON
14     IN
      

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                     *SEE INSTRUCTION BEFORE FILLING OUT!
         INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7
     (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE ATTESTATION.


                               Page 2 of 7 Pages