Karakhanov, R. A.; Vartanyan, M. M.; Apandiev, R. B.; Sharbatyan, P. A.; Brezhnev, L. Yu.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1984 , vol. 20, # 4 p. 356 - 358
Khimiya Geterotsiklicheskikh Soedinenii, 1984 , vol. 20, p. 448 - 450