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, # 4 p. 821 - 824 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1983 , # 4 p. 903 - 907