1. A. F. Ioffe and A. R. Regel, Progr. Semicond.,4, 237?291 (1960).
2. A. Z. Gadzhiev, Electrical and Optical Properties of Semiconductors [in Russian], Makhachkala (1980), p. 101.
3. B. T. Kolomiets, Phys. Status Solidi,7, 359-379, 713?731 (1964).
4. Z. U. Borisova, Chemistry of Glassy Semiconductors, Preparation and Properties [in Russian], Leningrad (1973).
5. N. Kh. Abrikosov, S. N. Kozlov, and V. F. Kisilev, Preparation and Properties of Semiconductor Compounds [in Russian], Moscow (1968), p. 62.