Stupnikova, T. V.; Petrenko, V. V. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1984 , vol. 20, # 10 p. 1140 - 1144 Khimiya Geterotsiklicheskikh Soedinenii, 1984 , vol. 20, # 10 p. 1383 - 1387