1. Hakobyan, R.S., Alaverdyan, R.B., Grigoryan, G.Kh., and Chilingaryan, Yu.S., Izv. AN Arm. SSR, Fizika, 1981, vol. 16, p. 77.
2. Raskutin, S.A., Radiotekhnika i elektronika, 1970, vol. 15, p. 2527.
3. Zolotov, E.M., Kiselev, V.A., and Sychugov, V.A., UFN, 1974, vol. 112, p. 231.
4. Arakelyan, S.M. and Chilingaryan, Yu.S., Nelineynaya optika zhidkikh kristallov (Nonlinear Optics of Liquid Crystals), Moscow: Nauka, 1984.
5. Arutunyan, V.M., Djotyan, G.P., and Karmenyan, A.V., Izv. AN Arm. SSR, Fizika, 1980, vol. 15, p. 379.