Filimonov, V. D.; Sukhoroslova, M. M.; Novikov, V. T.; Vidyagina, T. V. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1981 , vol. 17, # 12 p. 1213 - 1216 Khimiya Geterotsiklicheskikh Soedinenii, 1981 , vol. 17, # 12 p. 1654 - 1657