US2003003331-A1 -- US3453147-A   ;  US3592758-A   UNION OIL CO OF CALIFORNI (UNOC);  US3654139-A   BRPE (BRPE);  US3691060-A   T V INWOOD (INWO-Individual);  US3714030-A   BRITISH PETROLEUM CO LTD (BRPE);  US3877887-A   TEXACO DEV CORP (TEXC);  US4469590-A   EXXON RES & ENG CO (ESSO)   SCHUCKER R C,  WHEELOCK K S;  US5284717-A   PETRO ENERGY CENT (PETR-Non-standard);  SEKIYU SANGYO KASSE (SEKI-Non-standard);  SHOWA SHELL SEKIYU KK (SHEL)   KAMASE O,  MIURA T,  KUBOTA H;  US5565072-A   DE NORA PERMELEC SPA (ORON)   FAITA G,  MANTEGAZZA C;  US5686196-A   WESTINGHOUSE ELECTRIC CORP (WESE)   GEORGE R A,  SINGH P;  US6022634-A   DE NORA SPA (ORON)   RAMUNNI E,  FLEBA G,  BRAMBILLA M;  US6083425-A   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US6126908-A   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US20030023120-A1   ;  US20030105370-A1   ;  US20030162060-A1   ;  US6180842-B1   EXXON RES & ENG CO (ESSO)   BERLOWITZ P J,  WITTENBRINK R J,  COOK B R;  US6187465-B1   GALLOWAY T R (GALL-Individual)   GALLOWAY T R;  US6207122-B1   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US6254839-B1   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US1849-H   SASOL TECHNOLOGY PTY LTD (SASO)   FOURIE J H,  DE BOER J W;  US6884531-B2 -- US3453147-A   ;  US3592758-A   UNION OIL CO OF CALIFORNI (UNOC);  US3654139-A   BRPE (BRPE);  US3691060-A   T V INWOOD (INWO-Individual);  US3714030-A   BRITISH PETROLEUM CO LTD (BRPE);  US3877887-A   TEXACO DEV CORP (TEXC);  US4469590-A   EXXON RES & ENG CO (ESSO)   SCHUCKER R C,  WHEELOCK K S;  US5284717-A   PETRO ENERGY CENT (PETR-Non-standard);  SEKIYU SANGYO KASSE (SEKI-Non-standard);  SHOWA SHELL SEKIYU KK (SHEL)   KAMASE O,  MIURA T,  KUBOTA H;  US5565072-A   DE NORA PERMELEC SPA (ORON)   FAITA G,  MANTEGAZZA C;  US5686196-A   WESTINGHOUSE ELECTRIC CORP (WESE)   GEORGE R A,  SINGH P;  US6022634-A   DE NORA SPA (ORON)   RAMUNNI E,  FLEBA G,  BRAMBILLA M;  US6083425-A   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US6126908-A   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US20030023120-A1   ;  US20030105370-A1   ;  US20030162060-A1   ;  US6180842-B1   EXXON RES & ENG CO (ESSO)   BERLOWITZ P J,  WITTENBRINK R J,  COOK B R;  US6187465-B1   GALLOWAY T R (GALL-Individual)   GALLOWAY T R;  US6207122-B1   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US6254839-B1   LITTLE INC ARTHUR D (LITT)   CLAWSON L G;  US1849-H   SASOL TECHNOLOGY PTY LTD (SASO)   FOURIE J H,  DE BOER J W