1. S. Kataoka and H. Fujirsada, Bolid State Electronics, II, No. 1, 163 (1968).
2. M. S. Sodha, A. K. Arora, and P. K. Kaw, J. Phys., series 21, No. 1, 89 (1968).
3. V. N. Lugovoi, Zh. Éksperim. i Teor. Fiz.,41, No. 5, 1562 (1961).
4. A. I. Ansel'm, Introduction to the Theory of Semiconductors [in Russian], GIFML (1962).
5. D. A. Shekhter, in: Problems of Electronics Engineering [in Russian], Izd. SGU, Saratov (1972).