1. L. B. Dubrovskaya and P. V. Gel'd, ZhNKh,8, 1639 (1963).
2. V. P. Trusova, V. S. Kutsev, and B. F. Ormont, ZhNKh,5, 1119 (1960).
3. L. D. Dudkin and E. S. Kuznetsova, Poroshkovaya metallurgiya, 6, 20 (1962).
4. L. N. Guseva and B. I. Ovechkin, DAN SSSR,112, 681 (1957).
5. Shinoda, Asanabe, and Sasaki, Journ. of Phys. Soc. of Japan,19, No. 3 (1964).