1. A. I. Anselm, in Introduction to the Theory of Semiconductors (Nauka, Moscow, 1978; Prentice-Hall, Englewood Cliffs, 1981).
2. I. Barden, F. Blatt, and L. H. Hall, in Proceedings of the Atlantic City Photoconductivity Conference, New York, 1954, p. 146.
3. E. M. Kazarian, Phys. Lett. 19, 471 (1965).
4. A. A. Kirakosyan and E. A. Sarkisyan, Fiz. Tekh. Poluprovodn. (Leningrad) 17, 1629 (1977).
5. E. M. Kazaryan, K. A. Mkhoyan, and H. A. Sarkisyan, Thin Solid Films 302, 54 (1997).