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Application filed by Sverdlovskij Inzh Ped I, Srednee Professionalno Tekhn UfiledCriticalSverdlovskij Inzh Ped I
Priority to SU914905696ApriorityCriticalpatent/RU1769908C/en
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Publication of RU1769908CpublicationCriticalpatent/RU1769908C/en