Trapentsier, P. T.; Kalvin'sh, I. Ya.; Liepin'sh, E'. E'.; Lukevits, E'. Ya.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1983 , vol. 19, # 4 p. 391 - 394
Khimiya Geterotsiklicheskikh Soedinenii, 1983 , # 4 p. 481 - 485

Trapentsier, P. T.; Kalvin'sh, I. Ya.; Liepin'sh, E. E.; Lukevits, E.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1983 , vol. 19, # 9 p. 982 - 989
Khimiya Geterotsiklicheskikh Soedinenii, 1983 , # 9 p. 1227 - 1235