Röhren-Vademecum; P.H. Brans; Antwerpen p. 19
Universal Vade-Mecum, Electron Valves and Semiconductor Devices p. 35
Taschenbuch zum Röhren-Codex 1948/49
Babani, International Radio Tube Encyclopaedia
CV1331: W.H.
Wolfgang Holtmann
Just Qvigstad
CV1331: Manufacturer's Literature
Emilio Ciardiello
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