WO9508851-A1 -- EP415733-A   CANADA MIN NAT DEFENCE (MIND);  CANADIAN GOVERNMENT (CNDG)   WATKINS D S,  DIRCKS K W,  EPP D G;  US4910099-A   US DEPT ENERGY (USAT)   GOTTESFELD S;  US5108849-A   CANADA MIN NAT DEFENCE (MIND)   WATKINS D S,  DIRCKS K W,  EPP D G;  WO1994009523-A1   ;  CA1305212-C   CANADA MIN NAT DEFENCE (MIND)   WATKINS D S,  DIRCKS K W,  EPP D;  US4988583-A   CANADA MIN NAT DEFENCE (MIND);  CANADIAN GOVERNMENT (CNDG)   WATKINS D S,  DIRCKS K W,  EPP D G;  US5432021-A -- CA1305212-C   CANADA MIN NAT DEFENCE (MIND)   WATKINS D S,  DIRCKS K W,  EPP D;  US3088919-A   ;  US3216782-A   ;  US3216783-A   ;  US3615164-A   CONSOLIDATED NATURAL GAS (CON-Non-standard);  US3631073-A   ENGELHARD MINERALS & CHEM CORP (ENGH);  US3663162-A   INST GAS TECHNOLOGY (IGTE);  US3852169-A   DU PONT DE NEMOURS & CO E I (DUPO);  US4046956-A   UNITED TECHNOLOGIES CORP (UNAC)   FANCIULLO S;  US4234317-A   ;  US4293315-A   UNITED TECHNOLOGIES CORP (UNAC)   SEDERQUIST R A;  US4309359-A   IMPERIAL CHEM IND LTD (ICIL);  US4373452-A   CORNING GLASS WORKS (CORG)   VANDEWOEST R V,  VAN DEWOESTINE R V;  US4604275-A   ;  US4830844-A   PHILLIPS PETROLEUM CO (PHIP)   KOLTS J H;  US4906448-A      SAUVION G N,  CAILLOD J;  US4910099-A   US DEPT ENERGY (USAT)   GOTTESFELD S;  US4988583-A   CANADA MIN NAT DEFENCE (MIND);  CANADIAN GOVERNMENT (CNDG)   WATKINS D S,  DIRCKS K W,  EPP D G;  US5017357-A   PHILLIPS PETROLEUM CO (PHIP)   KOLTS J H,  TOOLEY P A,  BROWN S H;  US5061464-A   JOHNSON MATTHEY INC (JOHO)   CORDONNA G W,  BECKER E R;  US5079379-A   MONSANTO CO (MONS)   BRAUN J F,  NOWAK R T;  US5108849-A   CANADA MIN NAT DEFENCE (MIND)   WATKINS D S,  DIRCKS K W,  EPP D G;  US5176966-A   BALLARD POWER SYSTEMS INC (BLRD)   EPP D G,  WIENS B I;  US5252410-A   BALLARD POWER SYSTEMS INC (BLRD)   WILKINSON D P,  VOSS H H,  PRATER K B;  US5316747-A   BALLARD POWER SYSTEMS INC (BLRD)   POW E G,  TALABA M,  MCNEILLY L,  WATKINS D S,  LINES D A;  AU685845-B -- EP415733-A   CANADA MIN NAT DEFENCE (MIND);  CANADIAN GOVERNMENT (CNDG)   WATKINS D S,  DIRCKS K W,  EPP D G;  US4910099-A   US DEPT ENERGY (USAT)   GOTTESFELD S;  WO1994009523-A1   ;  EP720781-B1 -- EP415733-A   CANADA MIN NAT DEFENCE (MIND);  CANADIAN GOVERNMENT (CNDG)   WATKINS D S,  DIRCKS K W,  EPP D G;  US4910099-A   US DEPT ENERGY (USAT)   GOTTESFELD S;  WO1994009523-A1