Khlebnikov, A. F.; Kostik, E. I.; Kostikov, R. R. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1991 , vol. 27, # 6 p. 636 - 642 Khimiya Geterotsiklicheskikh Soedinenii, 1991 , vol. 27, # 6 p. 810 - 816