Laikhter, A. L.; Cherkasova, T. I.; Mel'nikova, L. G.; Ugrak, B. I.; Fainzil'berg, A. A.; Semenov, V. V. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 8.2 p. 1637 - 1643 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 8 p. 1849 - 1855