Vlasova,N.N. et al. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1979 , vol. 28, p. 1938 - 1940 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1979 , vol. 28, # 9 p. 2105 - 2107