1. D.A. Pinnow: IEEE J. QE-6, 223 (1970)
2. Topics Appl. Phys., Vol.7;JM Hammer,1979
3. See, for example, A. Yariv: Qunatum Electronics, 3rd edn. (Wiley, New York 1989) pp. 298–307
4. See, for example, J.F. Nye: Physical Properties of Crystals (Oxford Univ. Press, New York 1957) p. 123
5. Springer Ser. Solid-State Sci., Vol. 37,1988