1. S. J. Lippard and J. M. Berg, Principles of Bioinorganic Chemistry, University Science Books, California 1994.
2. D. E. Fenton, Bioinorganic Chemistry, Oxford University Press, Oxford 1995.
3. Y. Yoshikawa, E. Ueda, K. Kawabe, K. Miyabe, T. Takino, H. Sakurai and Y. Kojima, J. Biol. Inorg. Chem., 7 (2002) 68.
4. H. Schiff, Ann. Chem. Suppl., 3 (1864) 343.
5. H. Schiff, Ann. Chem., 150 (1869) 193.