Kruglov, D. E.; Safiev, O. G.; Zlot-skii, S. S.; Rakhmankulov, D. L.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1983 , vol. 19, # 9 p. 951 - 953
Khimiya Geterotsiklicheskikh Soedinenii, 1983 , # 9 p. 1192 - 1194