Babani, International Radio Tube Encyclopaedia p. 278 & 279
- - Manufacturers Literature
Universal Vade-Mecum, Electron Valves and Semiconductor Devices
Taschenbuch zum Röhren-Codex 1948/49
GU20: Manufacturer's Literature
Emilio Ciardiello
Just Qvigstad
GU20: Manufacturer's Literature
Emilio Ciardiello
Segue ...