Zav'yalov, S. I.; Kravchenko, N. E. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1989 , vol. 38, # 5.2 p. 1087 - 1090 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1988 , # 5 p. 1195 - 1198