Stezhko, T. V.; Solov'eva, N. P.; Kuleshova, E. F.; Granik, V. G. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1988 , vol. 24, p. 151 - 153 Khimiya Geterotsiklicheskikh Soedinenii, 1988 , vol. 24, # 2 p. 184 - 187