Orlova, T.I.; Ephstein, S.P.; Tashchi, V.P.; Rukasov, A.F.; Bogel'fer, L.Ya.; Putsykin, Yu.G. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1986 , vol. 22, # 4 p. 451 - 455 Khimiya Geterotsiklicheskikh Soedinenii, 1986 , vol. 22, # 4 p. 549 - 553