Belostotskii, A. M.; Shapiro, A. B.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1987 , vol. 23, # 6 p. 665 - 669
Khimiya Geterotsiklicheskikh Soedinenii, 1987 , vol. 23, # 6 p. 804 - 809