Zakharkin, L. I.; Petrushkina, E. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1982 , vol. 31, # 11 p. 2285 - 2286 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1982 , # 11 p. 2589 - 2590