Medvedeva, M. M.; Pozharskii, A. F.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1982 , vol. 18, # 8 p. 830 - 832
Khimiya Geterotsiklicheskikh Soedinenii, 1982 , vol. 18, # 8 p. 1086 - 1088