Prota G, Hu DN, Vincensi MR, McCormick SA, Napolitano A. Characterization of melanins in human irides and cultured uveal melanocytes from eyes of different colors. Exp Eye Res. 1998 Sep;67(3):293-9. PMID 9778410.
Wielgus AR & Sarna T. Melanin in human irides of different color and age of donors. Pigment Cell Res. 2005 Dec;18(6):454-64. PMID 16280011.
Oliphant LW. Pteridines and purines as major pigments of the avian iris. Pigment Cell Res. 1987 1(2):129-31. PMID 3507666.
Sturm RA & Frudakis TN. Eye colour: portals into pigmentation genes and ancestry. Trends Genet. 2004 Aug;20(8):327-32. PMID 15262401
Grant MD & Lauderdale DS. Cohort effects in a genetically determined trait: eye colour among US whites. Ann Hum Biol. 2002 Nov-Dec;29(6):657-66. PMID 12573082
Rebbeck TR, Kanetsky PA, Walker AH, Holmes R, Halpern AC, Schuchter LM, Elder DE, Guerry D. "P gene as an inherited biomarker of human eye color." Cancer Epidemiol Biomarkers Prev. 2002 Aug;11(8):782-4. PMID 12163334