;  US2002192531-A1 -- US3575719-A   ALLIS-CHALMERS MANUFACTUR (ALCM);  US4175165-A   ENGELHARD MINERALS CORP (ENGH)   ADLHART O J;  US4233369-A   UNITED TECHNOLOGIES CORP (UNAC)   BREAULT R D,  ROETHLEIN R J,  CONGDON J V;  US4562123-A   HITACHI LTD (HITA)   SHIMIZU T,  SATOU T,  TSUKUI T,  DOI R,  YAMAGUCHI M;  US4988583-A   CANADA MIN NAT DEFENCE (MIND);  CANADIAN GOVERNMENT (CNDG)   WATKINS D S,  DIRCKS K W,  EPP D G;  US5108849-A   CANADA MIN NAT DEFENCE (MIND)   WATKINS D S,  DIRCKS K W,  EPP D G;  US5252410-A   BALLARD POWER SYSTEMS INC (BLRD)   WILKINSON D P,  VOSS H H,  PRATER K B;  US5260143-A   BALLARD POWER SYSTEMS INC (BLRD)   VOSS H H,  WILKINSON D P,  WATKINS D S;  US5366818-A   BALLARD POWER SYSTEMS INC (BLRD)   WILKINSON D P,  VOSS H H,  WATKINS D S,  PRATER K B;  US5441819-A   BALLARD POWER SYSTEMS INC (BLRD)   VOSS H H,  WILKINSON D P,  WATKINS D S;  US5527363-A   BALLARD POWER SYSTEMS INC (BLRD)   WILKINSON D P,  LAMONT G J,  VOSS H H,  SCHWAB C;  US5629104-A   DETROIT CENT TOOL (DETR-Non-standard)   GOSTEK M,  CRAWFORD M H,  CRAWFORD M D,  WILSON C L;  US5683828-A   AEROJET GEN CORP (AERG)   SPEAR R G,  MUEGGENBURG H H,  HODGE R;  US5707755-A   GENERAL MOTORS CORP (GENK)   GROT S A;  US5723228-A   HONDA GIKEN KOGYO KK (HOND)   OKAMOTO T;  US5728446-A   JOHNSTON R P (JOHN-Individual);  SERVATIUS J A (SERV-Individual);  FEHR R T (FEHR-Individual)   JOHNSTON R P,  FEHR R T,  SERVATIUS J A;  US5804326-A   BALLARD POWER SYSTEMS INC (BLRD)   CHOW C Y,  WOZNICZKA B,  CHAN J K K;  US5858567-A   AEROJET GEN CORP (AERG)   SPEAR R G,  MUEGGENBURG H H,  HODGE R;  US5879826-A   ;  US5912088-A   PLUG POWER LLC (PLUG-Non-standard)   ERNST W D;  US5981096-A   DAIMLER-BENZ AG (DAIM)   LAMM A,  URBAN P,  HORNBURG G;  US6007933-A   PLUG POWER LLC (PLUG-Non-standard)   JONES D O;  US6015633-A   PLUG POWER LLC (PLUG-Non-standard)   CARLSTROM C M,  ACKER W P;  US6051331-A   AEROJET GEN CORP (AERG)   SPEAR R G,  MUEGGENBURG H H,  HODGE R;  US6071635-A   PLUG POWER LLC (PLUG-Non-standard)   CARLSTROM C M;  US6096450-A   PLUG POWER INC (PLUG-Non-standard)   WALSH M M