Dzhemilev, U. M.; Selimov, F. A.; Akhmetov, A. Zh.; Fatykhov, A. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1988 , vol. 37, # 10 p. 2102 - 2106 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1988 , # 10 p. 2335 - 2340