Soviet QSL cards , Wireless Receivers and Secret Agent Transmitters

Andy G0SFJ's presentation last night to Sutton and Cheam ARS can be downloaded here:
https://www.academia.edu/67999916/Soviet_QSL_Cards_and_Wireless

The presentation shows what the old QSL cards may reveal about the 1930s wireless technology in the Soviet Union, and describes two transmitters in use by Secret Agents in Japanese-occupied Manchuria. Was there only one Agent Sonja?