1. a) D.F. Evans, J. Chem. Soc. ( London ), 1959, p. 2003
2. concerning the adaptation of Evan’s method on organo-metallic complexes, see H.P. Fritz and K.E. Schwarzhans, J. Organomet. Chem. 1, 208 (1964)
3. H. Fischer, Dissertation, Technische Hochschule München, 1965
4. NMR of Paramagnetic Molecules, G.N. LaMar, W.deW. Horrocks, Jr. and R.H. Holm, Eds., Academic Press, New York and London, 1973
5. a) R. von Ammon and R.D. Fischer, Angew. Chem., Int. Ed. 11, 675(1972)