1. Deppe R, Pullmann H, Steigleder GK (1976) Dopa-positive cells and melanin in basal cell epithelioma ( BCE ). Arch Dermatol Res 256: 79–83
2. Fitzpatrick TB, Breathnach AS (1963) Das epidermale Melanin-Einheit-System. Dermatol Wochenschr 147: 481–489
3. Fitzpatrick TB, Szabó G, Seiji M, Quevedo WC Jr (1979) Biology of the melanin pigmentary system. In: Fitzpatrick TB, Eisen AZ, Wolff K, Freedberg IM, Austen KF (eds) Dermatology in general medicine. McGraw-Hill, New York, pp 131–163
4. Larsson B (1979) Mechanisms of accumulation of foreign substances in melanin. Binding to preformed melanin and incorporation into growing melanin. Acta Universitatis Upsaliensis, Uppsala
5. Lerner AB, Case JD (1959) Pigment cell regulatory factors. J Invest Dermatol 32: 211–223