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Priority claimed from FR8618063Aexternal-prioritypatent/FR2608408B1/fr
Priority claimed from FR8708354Aexternal-prioritypatent/FR2616646B1/fr
Application filed by Charbonnages De FrancefiledCriticalCharbonnages De France
Priority claimed from EP19870402959external-prioritypatent/EP0278197B1/de
Application grantedgrantedCritical
Publication of ATE57084T1publicationCriticalpatent/ATE57084T1/de