Pozharskii, A. F.; Dal'nikovskaya, V. V.; Pozharskaya, S. S.; Sheinkman, A. K. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1980 , p. 1064 - 1068 Khimiya Geterotsiklicheskikh Soedinenii, 1980 , vol. 16, # 10 p. 1398 - 1403