1. Yu. P. Kitaev, B. I. Buzykin, and L. P. Sysoeva, Zh. Organ. Khim., 8, 515 (1972).
2. T. Okamoto, M. Hirobe, and R. Sato, J. Pharm. Soc. Japan, 87, 994 (1967).
3. N. V. Dzhigirei, A. K. Sheinkman, and A. N. Kost, USSR Authors' Certificate No. 199,889 (1966);
4. Byul. Izobret., No. 16 (1967).
5. A. N. Kost, N. V. Baranova, A. K. Sheinkman, I. V. Komissarov, and A. S. Voyakin, Zh. Fiz. Khim., No. 5, 6 (1971).