Sagitullin, R. S.; Lugovik, B. A.; Shkil', G. P.; Zhelyaeva, I. M.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1984 , vol. 20, # 3 p. 340
Khimiya Geterotsiklicheskikh Soedinenii, 1984 , vol. 20, # 3 p. 417 - 418
Wright, Andrew D.; Bowen, Richard D.; Jennings, Keith R.
Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry (1972-1999), 1989 , p. 1521 - 1528