Vinogradova, O. V.; Kryshtalyuk, O. V.; Rudnev, M. I.; Pozharskii, A. F.; Kuz'menko, V. V. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1994 , vol. 30, # 10 p. 1182 - 1186 Khimiya Geterotsiklicheskikh Soedinenii, 1994 , # 10 p. 1364 - 1368