1. R.M. Baum, C&EN, July 30, 1997, p. 39.
2. R. Dagani, C&EN, January 22, 1996, p. 22.
3. J.-P. Launay, L'Actualité Chimique, July-August, 1994 p. 37.
4. D. Astruc, in: Electron Transfer and Radical Processes in Transition-Metal Chemistry, VCH, 1995, p. 283.