Guss, L. T.; Ershov, L. V.; Bogdanova, G. A.; Granik, V. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1990 , vol. 26, # 2 p. 183 - 188
Khimiya Geterotsiklicheskikh Soedinenii, 1990 , vol. 26, # 2 p. 215 - 220

Guss, L. T.; Ershov, L. V.; Granik, V. G.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1987 , vol. 23, # 12 p. 1368
Khimiya Geterotsiklicheskikh Soedinenii, 1987 , # 12 p. 1696