1. J. J. R. Frausto da Silva and R. J. P. Williams, The Biological Chemistry of the Elements, Clarendon Press, Oxford, 1991.
2. S.J. Lippard and J. M. Berg, Principles of Bioinorganic Chemistry, University Science Books, Mill Valley, California, 1994.
3. A. E. Martell and R. M. Smith, Critical Stability Constants, Vols. 1–6, Plenum Press, New York, 1974, 1975, 1976, 1977, 1982, 1989.
4. I. Bertini, C. Luchinat, W. Maret and M. Zeppezauer, Eds., Progress in Inorganic Biochemistry and Biophysics, Vol. 1, Zinc Enzymes, Birkhauser Verlag, Basel, 1986.
5. R. G. Pearson, J. Am. Chem. Soc., 1963, 85, 3533.