1. Arnow, L. E., Colorimetric determination of the components of 3, 4-dihydroxyphenylalanine-tyrosine mixtures. J. Biol. Chem.118, 531?537 (1937).
2. Boas, F., and Merkenschlager, F., Pflanzliche Tyrosinasen. Biochem. Z.155, 197?227 (1925).
3. Baldwin, E., Dynamic aspects of biochemistry, Cambridge, 1947.
4. Block, R. J. and Bolling, D., The amino acid composition of proteins and foods. Springfield, 1947.
5. de Bruyn, H. L. G., Het blauw worden van aardappelen. Tijdschr. Plantenziekten35, 185?222 (1929).