Tomilenko, E. I.; Ogoiko, P. I.; Staninets, V. I. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1987 , vol. 23, # 11 p. 1226 - 1228 Khimiya Geterotsiklicheskikh Soedinenii, 1987 , # 11 p. 1532 - 1533