Dzhemilev, U. M.; Selimov, F. A.; Khusnutdinov, R. A.; Fatykhov, A. A.; Khalilov, L. M.; Tolstikov, G. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 6.2 p. 1248 - 1253 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 6 p. 1407 - 1413