Tsizin, Yu. S.; Chernyak, S. A.; Timoshevskii, B. P.; Sergovskaya, N. L.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1985 , vol. 21, # 6 p. 705
Khimiya Geterotsiklicheskikh Soedinenii, 1985 , vol. 21, # 6 p. 847