Position, programs and instructions for special formation of the mouth of the spark telegraph

Regulations, programs and instructions for special formation of the mouth of the spark telegraph: project.- St. Petersburg: Type."T -in the artist of the press", 1910. -[2], 27 p.: table .. -Bibliogr.in the text..1. The people (collection).Electronic copy source: PBPlace of storage of the original: the Central Museum of Communications named after A.S.Popova