1) Prota, G.: Recent advances in chemistry of melanogenesis in mammals. J. Invest. Dermatol., 75: 122-127, 1980.
2) Prota, G.: Structure and biogenesis of pheomelanins, pigmentation: Its genesis and biologic control. Edited by V. Riley. New York, Appleton-Century-Crofts: pp615-630, 1972.
3) Raper, H.S.: XIV. The tyrosinase reaction V. Production from tyrosine of 5, 6-dihydroxyindole-2- carboxylic acid-the precursors of melanin. Biochem. J., 89-96, 1927.
4) Mason, H.S.: The chemistry of melanin. III. Mechanism of the oxidation of dihydroxyphenylalanine by tyrosinase. J. Biol. Chem., 172: 83-99, 1948.
5) Agrup, G., Agrup, P.: Urinary excretion of 5-S-Cysteinyldopa in patients with primary melanoma or melanoma metastasis. Acta Derm. Venereol., 55: 337-341, 1975.