Zakharkin, L. I.; Petrushkina, E. A. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1982 , vol. 31, p. 1683 - 1684 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1982 , # 8 p. 1892 - 1893