Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/100,659external-prioritypatent/US4820680A/en
Priority claimed from US07/100,662external-prioritypatent/US4810684A/en
Priority claimed from US07/100,661external-prioritypatent/US4810687A/en
Application filed by Shell Int ResearchfiledCriticalShell Int Research
Priority claimed from EP88202018Aexternal-prioritypatent/EP0309045B1/de
Application grantedgrantedCritical
Publication of ATE68722T1publicationCriticalpatent/ATE68722T1/de