Donchak, L. N.; Saverchenko, A. N.; Kaminskii, V. A.; Tilichenko, M. N.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1984 , vol. 20, # 7 p. 779 - 783
Khimiya Geterotsiklicheskikh Soedinenii, 1984 , # 7 p. 953 - 961