2) Wakamatsu K, Ito S: Seasonal variation in serum concentration of 5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid in healthy Japanese. Pigment Cell Res, 8: 132-134, 1995
3) Nimmo JE, Gawkrodger DJ, O'Docherty CStJ,: Plasma 5-S-cysteinyldopa as an index of melanogenesis. Br J Dermatol, 118: 487-496, 1988
4) Agrup G, Falck B, Fyge K,: Excretion of 5-S-cysteinyldopa in the urine of healthy subjects. Acta Dermato Venereol (Stockh) , 55: 7-9, 1975