1. B. V. Sokolov andI. A. Paribok-Alexandrovich, Bulletin Uch. Zap. of Volozodski Inst. (USSR),30, 64, 1966.
2. M. K. El-Mously, J. Neogr. Mat. (USSR),13, 801, 1977.
3. M. K. El-Mously, M. F. Kotkata andM. Fadel, Proc. Conf. Solid State Phys. and Relaxation Phenomena, 113–121, Cairo, 1977.
4. M. F. Kotkata, M. K. El-Mously andS. R. Atalla, Proc. 14th Int. Conf. on Thermal Conductivity, 39–44, USA, 1975.
5. M. Sugi, S. Iizima, M. Kikuchi andK. Tanaka, J. Non-Cryst. Solids,5, 358, 1971.