Ponomarev, I. I.; Vinogradova, S. V. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 10.2. p. 2229 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , vol. 39, # 10 p. 2457