Voronkov, M. G.; Gavrilova, G. A.; Chipanina, N. N.; Shulunova, A. M.; Gubanova, L. I.; et al. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1984 , vol. 33, p. 726 - 731 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1984 , # 4 p. 791 - 797