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Vaughn JE, Bradley KI, Byrd-Craven J, Kennison SM.Vaughn JE, et al.Evol Psychol. 2010 Aug 30;8(3):477-91. doi: 10.1177/147470491000800313.Evol Psychol. 2010.PMID: 22947814Free PMC article.Clinical Trial.