Balogh, Maria; Hermecz, Istvan; Szilagyi, Ildiko; Meszaros, Zoltan
Heterocycles, 1983 , vol. 20, # 6 p. 1083 - 1088

Smirnov, L. D.; Nikitin, S. V.; Chernyshev, A. I.; Sorokin, A. A.; Lezina, V. P.; et al.
Chemistry of Heterocyclic Compounds (New York, NY, United States), 1992 , vol. 28, # 12 p. 1425 - 1431
Khimiya Geterotsiklicheskikh Soedinenii, 1992 , # 12 p. 1660 - 1666