EXHIBIT A AGREEMENT JOINT FILING OF SCHEDULE 13G The undersigned hereby agree to jointly prepare and file with regulatory authorities a Schedule 13G and any future amendments thereto reporting each of the undersigned's ownership of securities of...

                                   EXHIBIT A

                                   AGREEMENT

                          JOINT FILING OF SCHEDULE 13G



     The  undersigned  hereby agree to jointly  prepare and file with regulatory
authorities a Schedule 13G and any future  amendments  thereto reporting each of
the undersigned's  ownership of securities of Sentigen Holding Corp. and hereby
affirm  that  such  Schedule  13G is  being  filed  on  behalf  of  each  of the
undersigned.




Date: April 23, 2001


By: /s/ J. Xxxxxx Xxxxx
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    J. Xxxxxx Xxxxx






Date: April 23, 2001
      X.X. Xxxxx Investment Banking Corp.




By:  /s/ Xxxxx Xxxxxxxx
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     Xxxxx Xxxxxxxx
     Treasurer