1. Author's Cert. (USSR) No. 697 510; Otkrytiya, No. 42 (1979).
2. G. A. Ermakova, S. Ya. Skachilova, V. G. Voronin, and Z. I. Shramova, Khim.-farm. Zh., No. 8, 963–971 (1983).
3. Netherlands App. No. 6 608 657; Chem. Abstr., P 11499d (1967).
4. L. P. Mykots and E. I. Raspopov, Farmatsiya, No. 4, 23–25 (1981).
5. M. V. Rubtsov and A. G. Baichikov, Synthetic Pharmaceuticals [in Russian], Moscow (1971), pp. 128–130.