1. J. M. Robertson and M. V. Van Tol, Thin Solid Films, Nos. 1?2, 221 (1984).
2. L. G. Volzhenskaya, Yu. V. Zorenko, N. I. Patsagan, et al., 5th All-Union Symposium on Luminescence Receivers and Transformers of Ionizing Radiation: Abstracts of Reports [in Russian], Tallinn, 1985, p. 37.
3. M. Kh. Ashurov, Yu. K. Voron'ko, V. V. Osiko, and A. A. Sobol', Spectroscopy of Crystals [in Russian], Moscow (1987), pp. 71?83.
4. L. G. Volzhenskaya, Yu. V. Zorenko, Yu. G. Dubov, et al., Zh. Prikl. Spektrosk.,44, No. 2, 303 (1986).
5. L. G. Volzhenskaya, Yu. V. Zorenko, N. I. Patsagan, and M. V. Pashkovskii, Opt. Spektrosk.,63, No. 1, 135 (1987).