1. Kantorovich and Krylov, Approximate Methods of Higher Analysis, Chap. IV, translation by C. D. Benster, Wiley, New York, 1964.
2. Harrington, R. F., Time-Harmonic Electromagnetic Fields, Chapter 7, McGraw-Hill, New York, 1961.
3. Berk, A. D., IRE Trans. on Antennas and Propagation AP-4 (1956) 104.
4. Slater, J. C., Microwave Electronics, Chapter 4, Van Nostrand, New York, 1950.
5. Interaction of Plasmas with High Intensity R-F Fields, research reports prepared under Contract No. AF 49(683)-1374 with Air Force Office of Scientific Research, Washington, D. C., 1964?65.