1. N. O. Sokal and A. D. Sokal, “High-efficiency tuned switching power amplifier,” U. S. Patent 3,919,656, Nov. 11, 1975 (now expired). [Includes a detailed technical description.]
2. -, “Class E — a new class of high-efficiency tuned single-ended switching power amplifiers,” IEEE J. Solid-State Circuits, vol. SC-10, no. 3, pp. 168–176, June 1975. [The text of [1] cut to half-length; retains the most-useful information. Text corrections are available from N. O. Sokal.]
3. F. H. Raab, “Idealized operation of the Class E tuned power amplifier,” IEEE Trans. Circuits and Systems, vol. CAS-24, no. 12, pp. 725–735, Dec. 1977.
4. N. O. Sokal and A. D. Sokal, “Class E switching-mode RF power amplifiers — low power dissipation, low sensitivity to component tolerances (including transistors), and well-defined operation,” Proc. 1979 IEEE ELECTRO Conference, Session 23, New York, NY, 25 April 1979; reprinted in R.F. Design, vol. 3, no. 7, pp. 33–38, 41, July/Aug. 1980. [Includes plots of efficiency vs. frequency with Q L as a parameter and efficiency vs. variations of all circuit parameters.]
5. M. K. Kazimierczuk and K. Puczko, “Analysis of Class E tuned power amplifier at any Q and switch duty cycle,” IEEE Trans. Circuits and Systems, vol. CAS-34, no. 2, pp. 149–159, Feb. 1987.