1. Kh. Vakhmer and Yu. M. Tairov, Fiz. Tverd. Tela (Leningrad) 11, 2400 (1969) [Sov. Phys. Solid State 11, 1944 (1969)].
2. G. A. Lomakina, V. I. Sokolov, and Yu. A. Vodakov, Fiz. Tekh. Poluprovodn. 16, 1244 (1982) [Sov. Phys. Semicond. 16, 795 (1982)].
3. V. S. Ballandovich, Fiz. Tekh. Poluprovodn. 25, 287 (1991) [Sov. Phys. Semicond. 25, 174 (1991)].
4. Yu. A. Vodakov, G. A. Lomakina, E. N. Mokhov, V. G. Oding, V. V. Semenov, and V. I. Sokolov, in Problems in the Physics and Technology of Wide-Gap Semiconductors [in Russian], Leningrad (1979), p. 164.
5. P. G. Baranov, N. G. Romanov, V. A. Vetrov, and V. G. Oding, in Proceedings of the 20th International Conference on the Physics of Semiconductors, Vol. 3, E. M. Anastasskis and J. D. Joannopoulos (Eds.), World Scientific, Singapore (1990), p. 1855.