Pudovik, A. N.; Khairullin, V. K.; Vasyanina, M. A.; Pokrovskaya, I. K.; Kataeva, O. N.; et al. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1990 , vol. 39, # 11 p. 2345 - 2348 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1990 , # 11 p. 2590 - 2593