1. 1. M.V. Shevchuk, V.V. Atuchin, A.V. Kityk, A.O. Fedorchuk, Y.E. Romanyuk, S. Calus, O.M. Yurchenko, and O.V. Parasyuk, J. Cryst. Growth 318, 708 (2011).
2. 2. V.L. Bonch-Bruevich, R. Enderlein, B. Esser, R. Keiper, A.G. Mironov, and I.P. Zvyagin, Elektronentheorie Ungeordneter Halbleiter (Deutscher Verlag der Wissenschaften, Berlin, 1984).
3. 3. L.S. Stilbans, Physics of Semiconductors (Sovetskoe Radio, Moscow, 1967) (in Russian).
4. 4. N.F. Mott and E.A. Davies, Electronic Processes in Non-Crystalline Materials (Oxford University Press, Oxford, 1979).
5. 5. N.A. Vainshtein, A.F. Zatsepin, V.S. Kortov, and Yu.V. Shchapova, Fiz. Tverd. Tela 42, 224 (2000).