Dettwyler, K. A. «Duration of breast feeding and adult arterial distensibility. Humans are primates, designed to breast feed for years not months.» BMJ. 2001 Sep 22;323(7314):689-90 Dispoñible en: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121244/?tool=pubmed] Consultado el 28 de novembro de 2009.