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.)
Publication of NL255470ApublicationCriticalpatent/NL255470A/xx
Priority claimed from FR807259Aexternal-prioritypatent/FR1246829A/fr
Priority claimed from FR827681Aexternal-prioritypatent/FR1265336A/fr