1. Mechanisms that cause abnormal skin color: J.P. Ortonne and J. Nordlund : page 28,521–537. The Pigmentary System : Second Edition (Blackwell Publishing 2006) Ed. J.J. Nordlund, R.E. Boissy, V.J. Hearing, R.A. King, W.S. Oetting, et J.P. Ortonne.
2. Fitzpatrick TB, Ortonne JP. Normal Skin color and General Considerations of Pigmentary Disorders Section 12, 819–826, Volume 1 Ed. McGram- Hill 2003.