Sokolenko, V. A.; Svirskaya, N. M.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1987 , vol. 23, # 6 p. 675 - 677
Khimiya Geterotsiklicheskikh Soedinenii, 1987 , vol. 23, # 6 p. 817 - 819