Pazenok, S. V.; Kondratenko, N. V.; Popov, V. I.; Troitskaya, V. I.; Il'chenko, A. Ya.; et al.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1983 , vol. 19, # 11 p. 1182 - 1187
Khimiya Geterotsiklicheskikh Soedinenii, 1983 , # 11 p. 1493 - 1499