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Priority claimed from FR45244Aexternal-prioritypatent/FR1469635A/fr
Priority claimed from FR45243Aexternal-prioritypatent/FR1469634A/fr
Application filed by Houilleres Du Bassin Du Nord & Du Pas De CalaisfiledCriticalHouilleres Du Bassin Du Nord & Du Pas De Calais
Publication of DK140263BpublicationCriticalpatent/DK140263B/da
Application grantedgrantedCritical
Publication of DK140263CpublicationCriticalpatent/DK140263C/da