Al'fonsov, V. A.; Trusenev, A. G.; Batyeva, E. S.; Pudovik, A. N.; Pudovik, M. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 9.2 p. 1862 - 1869 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 9 p. 2103 - 2111