Krapivin, G. D.; Kul'nevich, V. G.; Val'ter, N. I.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1986 , vol. 22, # 10 p. 1072 - 1075
Khimiya Geterotsiklicheskikh Soedinenii, 1986 , vol. 22, # 10 p. 1325 - 1329