Mironov, V. F.; Mavleev, R. A.; Konovalova, I. V.; Ofitserov, E. N.; Pudovik, A. N. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1991 , vol. 40, # 4.2 p. 841 - 843 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1991 , # 4 p. 946 - 948