Keiko, N. A.; Musorina, T. N.; Frolov, Yu. L.; Shulunova, A. M.; Chuvashov, Yu. A.; Voronkov, M. G. Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science (English Translation), 1981 , vol. 30, # 9 p. 1634 - 1636 Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1981 , vol. 30, # 9 p. 1993 - 1996