1. S. I. Berul, V. B. Lazarev, and A. V. Salov, Zh. Neorg. Khim.,16, 3363 (1971).
2. V. A. Bazakutsa, N. I. Gnidash, V. B. Lazarev, E. I. Rogacheva, A. V. Salov, L. N. Sukhorukova, M. P. Vasil'eva, and S. I. Berul, Zh. Neorg. Khim.,18, 3234 (1973).
3. V. M. Mogilevskii and A. F. Chudnovskii, Thermal Conductivity of Semiconductors [in Russian], Nauka, Moscow (1972).
4. E. A. Petrov and E. L. Strum, Fiz. Tverd. Tela,4, 6 (1962).
5. D. P. Spitzer, J. Phys. Chem. Solids,31, No. 1, 19 (1970).