Ryzhkina, I. S.; Kudryavtseva, L. A.; Bel'skii, V. E.; Ivanov, B. E. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 3.1 p. 478 - 482 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 3 p. 555 - 560