Kamalov, R. M.; Makarov, G. M.; Kataeva, O. N.; Musin, R. Z.; Litvinov, I. A.; et al. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 2.2 p. 396 - 403 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 2 p. 460 - 467