Tertov, B.A.; Bogachev, Yu.G.; Koshchienko, Yu.V.; Suvorova, G.M.; Tsupak, E.B.; et al. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1986 , vol. 22, # 8 p. 868 - 872 Khimiya Geterotsiklicheskikh Soedinenii, 1986 , # 8 p. 1073 - 1077