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Priority claimed from GB888820008Aexternal-prioritypatent/GB8820008D0/en
Priority claimed from GB8911661Aexternal-prioritypatent/GB8911661D0/en
Application filed by Derek Robert MarsdenfiledCriticalDerek Robert Marsden
Priority claimed from EP19890909584external-prioritypatent/EP0431014B1/en
Application grantedgrantedCritical
Publication of ATE90164T1publicationCriticalpatent/ATE90164T1/en