Pudovik, M. A.; Ostanina, I. L.; Pudovik, A. N. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1983 , vol. 32, # 8 p. 1683 - 1686 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1983 , # 8 p. 1859 - 1863