Ito, S.; Wakamatsu, K. (2011). «Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin». Journal of the European Academy of Dermatology and Venereology. 25 (12): 1369–1380. PMID22077870. doi:10.1111/j.1468-3083.2011.04278.x
Ito, S.; Wakamatsu, K. (2011). «Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin». Journal of the European Academy of Dermatology and Venereology. 25 (12): 1369–1380. PMID22077870. doi:10.1111/j.1468-3083.2011.04278.x