Vakhitova, M. Sh.; Pantukh, B. I.; Tolstikov, G. A.; Yablonskii, O. P.; Svitych, R. B. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1987 , vol. 36, # 8 p. 1675 - 1677 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1987 , # 8 p. 1808 - 1810