1. N. N. Greenwood and A.Earnshaw, Chemistry of the Elements, Butterworth, Oxford, 2nd edn, 1997
2. F. A. Cotton , G.Wilkinson, C. A.Murillo and M.Bochmann, Advanced Inorganic Chemistry, Wiley, NY, 6th edn, 1999
3. R. V. Parish , The Metallic Elements, Longman, London, 1977
4. S. Mann , Biomineralisation, OUP, Oxford, 2001
5. W. E. Lindsell , in Comprehensive Organometallic Chemistry II, ed. G. Wilkinson, F. G. A. Stone and E. W. Abel, Elsevier, Oxford, 1995, vol. 1, p. 57