Vainilabichus, P. I.; Tumkyavichyus, S. P.; Denene, A. A.; Rochka, V.-S. M.; Lautsyuvene, I. Pharmaceutical Chemistry Journal, 1984 , vol. 18, # 11 p. 775 - 779 Khimiko-Farmatsevticheskii Zhurnal, 1984 , vol. 18, # 11 p. 1335 - 1339