Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) THOMSEN R,Sperm competition and the function of male masturbation in non-human primates,Sexual selection and reproductive competition in primates : new perspectives and directions,,American Society of Primatologists,2003,,,,https://cir.nii.ac.jp/crid/1572261550101187840,