Finkel'shtein, E. Sh.; Fedorov, V. E.; Filatova, M. P. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 4.2 p. 853 - 854 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 4 p. 958 - 960