http://www.valvewizard.co.uk/index.html
http://www.valvewizard.co.uk/pentode.html
http://www.valvewizard.co.uk/gridstopper.html
https://spectrum.ieee.org/the-cool-sound-of-tubes
http://www.tubebooks.org/tubedata/rc30.pdf
http://www.tubebooks.org/Books/PrinciplesOfElectronics.pdf
Theory and Operating Characteristics of the Thermionic Amplifier
- H.J. van der Bijl, Western Electric Company, Inc., NY, USA
- Published in: Proceedings of the Institute of Radio Engineers ( Volume: 7, Issue: 2, April 1919)
The Thermionic Vacuum Tube and it's applications
- H.J. van der Bijl
- McGraw-Hill Book Company, Inc. 1920