Nemeryuk, M. P.; Sedov, A. L.; Krepelka, I.; Benes, Ya.; Safonova, T. S. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1983 , p. 1113 - 1115 Khimiya Geterotsiklicheskikh Soedinenii, 1983 , vol. 19, # 10 p. 1398 - 1400