Degutis, Yu. A.; Schachkus, A. A.; Urbonavichyus, A. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1985 , vol. 21, # 7 p. 774 - 777
Khimiya Geterotsiklicheskikh Soedinenii, 1985 , # 7 p. 933 - 935