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 DE2540201Aexternal-prioritypatent/DE2540201C2/en
Application filed by Opti AgfiledCriticalOpti Ag
Publication of ZA765266BpublicationCriticalpatent/ZA765266B/en