1. D.A. Pinnow: IEEE J. QE-6, 223 (1970)
2. J.M. Hammer: Modulation and switching of light in dielectric waveguides, in Integrated Optics, 2nd edn., ed. by T. Tamir, Topics Appl. Phys., Vol. 7 ( Springer, Berlin, Heidelberg 1979 ) p. 142
3. See, for example, A. Yariv: Quantum 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. L.A. Shuvalov (ed.): Modern Crystallography IV, Springer Ser. Solid-State Sci., Vol. 37 ( Springer, Berlin, Heidelberg 1988 )