Mayell, Hillary. “Documentary Redraws Humans' Family Tree“ (summarizing Hedges' quote, 2003. Human Diversity – The Journey of Man: A Genetic Odyssey, National Geographic Documentary)
ucla.edu
cogweb.ucla.edu
Frost, Peter. „Why Do Europeans Have So Many Hair and Eye Colors? „ (summarizing Frost, P. 2006. European hair and eye color – A case of frequency-dependent sexual selection? Evolution and Human Behavior 27:85-103)