Sorokin, V. L.; Azzuz, A. A.; Kulinovich, O. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1991 , vol. 27, # 3 p. 271 - 272
Khimiya Geterotsiklicheskikh Soedinenii, 1991 , # 3 p. 334 - 336