Zelenov, M. P.; Frolova, G. M.; Mel'nikova, S. F.; Tselinskii, I. V. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1982 , vol. 18, # 1 p. 21 - 23 Khimiya Geterotsiklicheskikh Soedinenii, 1982 , vol. 18, # 1 p. 27 - 29