Freidlin, G. N.; Glushkova, A. A.; Solop, K. A. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1982 , vol. 18, # 2 p. 127 - 130 Khimiya Geterotsiklicheskikh Soedinenii, 1982 , vol. 18, # 2 p. 167 - 170