1. Watson, J. D.: Molecular Biology of the Gene. New York: W. A. Benjamin 1970, Second Edition.
2. Theorell, H.: Advan. Enzymol. 7, 265 (1947).
3. Bearden, A. J., Dunham, W. R.: Struct. Bonding 8, 1 (1970).
4. Neilands, J. B.: In: Inorganic Biochemistry; edited by Eichhorn, G. New York: Elsevier 1972.
5. Zuckerkandl, E., Pauling, L.: J. Theoret. Biol. 8, 357 (1965).