Kibardin, A. M.; Gryaznov, P. I.; Gazizov, T. Kh.; Pudovik, A. N. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1987 , vol. 36, # 8 p. 1693 - 1695 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1987 , # 8 p. 1826 - 1828