1. Wood JW. “High Efficiency Class C Amplifier,” U.S. Patent 3,430,157, February 1969.
2. Operation of Vacuum-Tube Generator on Detuned Resonant Circuit (in Russian);Khmelnitsky,1962
3. Ewing GD. High-Efficiency Radio-Frequency Power Amplifiers, Ph.D. Dissertation, Oregon State University; June 1964.
4. Amplifiers has 85% efficiency while providing up to 10 watts power over a wide frequency band;Lohrmann;Electronic Design,1966
5. Switching mode of high frequency power amplifiers (in Russian);Artym;Radiotekhnika,1969