1. Yu. V. Kizhevnikov, N. N. Smirnova, V.S. Zalesov, et al., Khim.-farm. Zh., No. 6, 55–59 (1981).
2. B. V. Shetty, U.S. Patent 3,577,117, Ref. Zh. Khim., No. 23, 23H367 (1971).
3. K. Okumura, T. Oine, Y. Yamada, et al., J. Med. Chem.,11, 348–352 (1968).
4. T. Yabuuti, Kh. Fudzimura, T. Khommura, et al., Jap. Patent 492,759, Ref. Zh. Khim., No. 9, 90257 (1975).
5. B. Danielsson and L. Kronberg, Acta Pharm. Suec.,6, 379–389 (1969).