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Priority claimed from US06/230,035external-prioritypatent/US4725837A/en
Application filed by Tele Drill IncfiledCriticalTele Drill Inc
Publication of NO822925LpublicationCriticalpatent/NO822925L/en
Publication of NO157591BpublicationCriticalpatent/NO157591B/en
Publication of NO157591CpublicationCriticalpatent/NO157591C/en