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Priority claimed from DER24403Aexternal-prioritypatent/DE1146073B/de
Priority claimed from DER24554Aexternal-prioritypatent/DE1149725B/de
Application filed by Wilhelm Ritzerfeld, Gerhard RitzerfeldfiledCriticalWilhelm Ritzerfeld
Publication of BE584753ApublicationCriticalpatent/BE584753A/fr