1. P. A. Petyunin and Z. G. Kalugina, Zh. Obshch. Khim.,33, 2835 (1963).
2. R. B. Hoffet, J. Med. Pharm. Chem.,7, 319 (1964).
3. Heino A. Luts, W. Zucarelo, and I. Grattan, J. Pharm. Sci.,54, 460 (1965).
4. French Patent No. 2082 M; Ref. Zh. Khimiya No. 9H263 (1966).
5. M. D. Mashkovskii, Medicinal Agents [in Russian], Supplement 1, Moscow (1964), p. 25.