1. Theorell, H., and Akesson, A., J. Amer. Chem. Soc., 63, 1812, 1818, 1820 (1941).
2. George, P., Glauser, S. C., and Schejter, A., in Molecular Basis for Enzyme Action and Inhibition, edit. by Desnuelle, P., Proc. Fifth Cong. Biochem., Moscow, 1961, 4, 192 (Pergamon Press, Oxford, 1963).
3. George, P., and Lyster, R. L. J., Proc. U.S. Nat. Acad. Sci., 44, 1013 (1958).
4. See Lemberg, R., and Legge, J. W., Hematin Compounds and Bile Pigments (Interscience, New York, 1949).
5. Scheller, W., Salewski, A., and Jung, F., Biochem. Z., 326, 288 (1955).