Terenin, V. I.; Kabanova, E. V.; Bundel', Yu. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1991 , vol. 27, # 6 p. 597 - 600
Khimiya Geterotsiklicheskikh Soedinenii, 1991 , vol. 27, # 6 p. 763 - 766