1. Handbook of Physical Quantities, edited by I. S. Grigor’ev and E. Z. Meilikhov [in Russian] (Énergoatomizdat, Moscow, 1991).
2. N. W. Ashcroft and N. D. Mermin, Solid State Physics (Holt, Rinehart and Winston, New York, 1976).
3. J. I. Pankove, Optical Processes in Semiconductors (Prentice-Hall, Englewood Cliffs, N.J., 1971).
4. K. V. Shalimova, Physics of Semiconductors [in Russian] (Énergiya, Moscow, 1976).
5. Y. P. Varshni, Physica (Amsterdam) 34, 149 (1967).