EP787679-A1 -- DE4420753-A1   DAIMLER-BENZ AG (DAIM)   HEIL D,  BENZ U;  EP306945-A   PHILLIPS PETROLEUM CO (PHIP)   KOLTS J H;  EP650922-A1   ;  EP650923-A1   DAIMLER-BENZ AG (DAIM)   PLOG C,  MAUNZ W,  STENGEL T,  ANDORF R;  EP306945-B1   PHILLIPS PETROLEUM CO (PHIP)   KOLTS J H;  EP650923-B1   DAIMLER-BENZ AG (DAIM)   PLOG C,  MAUNZ W,  STENGEL T,  ANDORF R;  JP04250851-A   ;  JP63274063-A   ;  US3615164-A   CONSOLIDATED NATURAL GAS (CON-Non-standard);  US3631073-A   ENGELHARD MINERALS & CHEM CORP (ENGH);  US4840783-A   INST FRANCAIS DU PETROLE (INSF)   VU Q D,  DAVIDSON M,  DURAND D,  COURTY P;  US4847231-A   GAS RES INST (GASR-Non-standard)   GRATZEL M,  KIWI J,  THAMPI K R;  US4865624-A   NIPPON SANSO KK (NIIO)   OKADA H;  DE19603222-C1 -- EP650922-A1   ;  EP650923-A1   DAIMLER-BENZ AG (DAIM)   PLOG C,  MAUNZ W,  STENGEL T,  ANDORF R;  US3615164-A   CONSOLIDATED NATURAL GAS (CON-Non-standard);  US3631073-A   ENGELHARD MINERALS & CHEM CORP (ENGH);  US4840783-A   INST FRANCAIS DU PETROLE (INSF)   VU Q D,  DAVIDSON M,  DURAND D,  COURTY P;  US5904913-A -- DE4420753-A1   DAIMLER-BENZ AG (DAIM)   HEIL D,  BENZ U;  EP306945-A   PHILLIPS PETROLEUM CO (PHIP)   KOLTS J H;  EP650922-A1   ;  EP650923-A1   DAIMLER-BENZ AG (DAIM)   PLOG C,  MAUNZ W,  STENGEL T,  ANDORF R;  JP04250851-A   ;  JP62105901-A   ;  JP63274063-A   ;  US3615164-A   CONSOLIDATED NATURAL GAS (CON-Non-standard);  US3631073-A   ENGELHARD MINERALS & CHEM CORP (ENGH);  US4840783-A   INST FRANCAIS DU PETROLE (INSF)   VU Q D,  DAVIDSON M,  DURAND D,  COURTY P;  US4847231-A   GAS RES INST (GASR-Non-standard)   GRATZEL M,  KIWI J,  THAMPI K R;  US4865624-A   NIPPON SANSO KK (NIIO)   OKADA H;  US4946667-A   ENGELHARD MINERALS CORP (ENGH)   BESHTY B S,  WHELAN J A;  US5093102-A   INST FRANCAIS DU PETROLE (INSF)   DURAND D,  ORIEUX A,  COURTY P,  MOURATOFF S;  EP787679-B1 -- DE4420753-A1   DAIMLER-BENZ AG (DAIM)   HEIL D,  BENZ U;  EP306945-A   PHILLIPS PETROLEUM CO (PHIP)   KOLTS J H;  EP650922-A1   ;  JP04250851-A   ;  JP63274063-A   ;  US4847231-A   GAS RES INST (GASR-Non-standard)   GRATZEL M,  KIWI J,  THAMPI K R;  US4865624-A   NIPPON SANSO KK (NIIO)   OKADA H;  EP650923-A1   DAIMLER-BENZ AG (DAIM)   PLOG C,  MAUNZ W,  STENGEL T,  ANDORF R;  US3615164-A   CONSOLIDATED NATURAL GAS (CON-Non-standard);  US3631073-A   ENGELHARD MINERALS & CHEM CORP (ENGH);  US4840783-A   INST FRANCAIS DU PETROLE (INSF)   VU Q D,  DAVIDSON M,  DURAND D,  COURTY P