Kuroyan, R. A.; Sarkisyan, V. V.; Vartanyan, S. A. Chemistry of Heterocyclic Compounds (New York, NY, United States), 1986 , vol. 22, # 12 p. 1354 - 1357 Khimiya Geterotsiklicheskikh Soedinenii, 1986 , vol. 22, # 12 p. 1673 - 1676