Tomilov, Yu. V.; Kostitsyn, A. B.; Dokichev, V. A.; Dzhemilev, U. M.; Nefedov, O. M. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. <1> 38, # 12 p. 2518 - 2521 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1989 , # 12 p. 2752 - 2755