Vvedenskii, V.Yu.; Shtefan, E.D.; Malyushenko, R.N.; Deryagina, E.N.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1994 , vol. 30, # 7 p. 767 - 770
Khimiya Geterotsiklicheskikh Soedinenii, 1994 , # 7 p. 891 - 895