Source: https://www.researchgate.net/profile/Maria-Mesa-10/publication/240980124_Analyse_de_la_variabilite_de_la_pigmentation_de_la_peau_durant_la_croissance/links/581633f608aeb720f6880944/Analyse-de-la-variabilite-de-la-pigmentation-de-la-peau-durant-la-croissance.pdf