Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by П.П. СурминfiledCriticalП.П. Сурмин
Priority to SU411ApriorityCriticalpatent/SU72677A1/ru
Application grantedgrantedCritical
Publication of SU72677A1publicationCriticalpatent/SU72677A1/ru