1. D. Marcuse:Light Transmission Optics, Bell Laboratories Series 2 (New York, 1972), p. 297.
2. M. M. Barlow andJ. Brown:Radio Surface Waves (London, 1962), p. 64.
3. S. P. Schlesinger, P. Diament andA. Vigants:Trans. IEEE on MTT, MTT-8, 252 (1960).
4. Y. Garault:Compt. Rend.,24, 843 (1962).
5. F. J. Rosenbaum:Journ. Quant. Electron., QE-1, 367 (1965).