----------------- CUSIP No. 928753102 13G Page 7 of 9 Pages ------------------- ----------------- EXHIBIT 1 TO SCHEDULE 13G FEBRUARY 4, 1997 MORGAN STANLEY GROUP INC. and MORGAN STANLEY & CO. INCORPORATED hereby agree that, unless differentiated, this...

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CUSIP No. 000000000                   13G                      Page 7 of 9 Pages
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                            EXHIBIT 1 TO SCHEDULE 13G


                                FEBRUARY 4, 1997


    XXXXXX  XXXXXXX  GROUP  INC.  and  XXXXXX  XXXXXXX  &  CO.  INCORPORATED

hereby agree that, unless differentiated, this Schedule 13G is filed on  

behalf of each of the parties.


            XXXXXX  XXXXXXX  GROUP INC.


   BY:      /s/ Xxxxxx X. Xxxxxxx
            --------------------------------------------------------------------
            Xxxxxx X. Xxxxxxx / Vice-President Xxxxxx Xxxxxxx & Co. Incorporated


            XXXXXX  XXXXXXX & CO. INCORPORATED


   BY:      /s/ Xxxxxx X. Xxxxxxx
            --------------------------------------------------------------------
            Xxxxxx X. Xxxxxxx / Vice-President Xxxxxx Xxxxxxx & Co. Incorporated