Age-related variation in sexual behaviours among heterosexual men residing in Brazil, Mexico and the USA.
August EM, Daley E, Kromrey J, Baldwin J, Romero-Daza N, Salmeron J, Lazcano-Ponce E, Villa LL, Bryant CA, Giuliano AR. Age-related variation in sexual behaviours among heterosexual men residing in Brazil, Mexico and the USA. J Fam Plann Reprod Health Care. 2014 Oct; 40(4):261-9.