Dzhemilev, U. M.; Baibulatova, N. Z.; Tkachenko, T. K.; Kunakova, R. V.; Khalilov, L. M.; Berg, A. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. 38, # 3.2 p. 581 - 586 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1989 , # 3 p. 655 - 660