Dovgilevich, A.V.; Golubeva, G. A.; Malkov, A.V.; Sviridova, L. A.; Bundel', Yu. G. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1984 , vol. 20, # 1 p. 85 - 89 Khimiya Geterotsiklicheskikh Soedinenii, 1984 , vol. 20, # 1 p. 101 - 105