1. I. P. Kuz'mina and V. A. Nikitenko, Preparation and Optical Properties of Zinc Oxide [in Russian], Moscow (1984).
2. L. N. Kurbatov, G. S. Kozina, V. S. Kostinskaya, et al., Kvantovaya Élektron. (Moscow),7, 378 (1978).
3. V. A. Nikitenko, A. I. Tereshchenko, I. P. Kuz'mina, and A. N. Lobachev, Opt. Spektrosk.,50, No. 3, 605 (1981).
4. A. I. Proskura and V. Ya. Degoda, Zh. Prikl. Spektrosk.,37, No. 1, 71 (1982).
5. A. I. Proskura and I. V. Zakharchenko, Zh. Prikl. Spektrosk.,45, No. 3, 434 (1986).