1. N. I. Ionov, Dokl. Akad. Nauk SSSR, 59: 467 (1948).
2. M. Ya. Gen and Yu. I. Petrov, Usp. Khim., 38: 2249 (1969).
3. G. Rothberg, M. Eisenstadt, and P. Kush, J. Chem. Phys., 30: 604 (1959).
4. V. M. Bulakh, J. Crystal Growth, 5: 243 (1969).
5. Yu. N. Lybitov, Yu. A. Gel’man, A. M. Zatselyapin, V. I. Mikhailov, and L. V. Suman, Prib. Tekh. Eksp., No. 3, 218 (1969), VINITI, No. 525–69 Dep.