Ivashchenko, A. V.; Lazareva, V. T.; Prudnikova, E. K.; Ivashchenko, S. P.; Rumyantsev, V. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1982 , vol. 18, # 2 p. 185 - 189
Khimiya Geterotsiklicheskikh Soedinenii, 1982 , # 2 p. 236 - 241