Fakhretdinov, R. N.; Telin, A. G.; Dzhemilev, U. M. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1985 , vol. 34, p. 2560 - 2563 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1985 , # 12 p. 2763 - 2766