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Application filed by Ф.А. Попутников, Н.П. ЧижевскийfiledCriticalФ.А. Попутников
Priority to SU79582ApriorityCriticalpatent/SU30670A1/en
Application grantedgrantedCritical
Publication of SU30670A1publicationCriticalpatent/SU30670A1/en