Dzhemilev, U. M.; Khusnutdinov, R. I.; Shchadneva, N. A.; Tolstikov, G. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 7.2 p. 1447 - 1450 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , # 7 p. 1598 - 1601