Beecham Group Limited
Patent: US3974289 A1, 1976 ;

Mozhaeva, T. Ya.; Samsonova, O. L.; Savel'ev, V. L.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1988 , vol. 24, # 9 p. 1070
Khimiya Geterotsiklicheskikh Soedinenii, 1988 , # 9 p. 1287

Mozhaeva, T. Ya.; Samsonova, O. L.; Savel'ev, V. L.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1988 , vol. 24, # 9 p. 1070
Khimiya Geterotsiklicheskikh Soedinenii, 1988 , # 9 p. 1287