Zhdanov, Yu. A.; Zvezdina, E. A.; Statsenko, S. M.; Maksimova, A. N. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1987 , vol. 23, # 2 p. 149 - 154 Khimiya Geterotsiklicheskikh Soedinenii, 1987 , vol. 23, # 2 p. 182 - 187