Shklyaev, V. S.; Aleksandrov, B. B.; Legotkina, G. I.; Vakhrin, M. I.; Gavrilov, M. S.; Mikhailovskii, A. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1983 , vol. 19, # 11 p. 1242
Khimiya Geterotsiklicheskikh Soedinenii, 1983 , # 11 p. 1560