Age-Specific prevalence of anal human papillomavirus infection in HIV-negative sexually active men who have sex with men: the EXPLORE study.

Chin-Hong PV, Vittinghoff E, Cranston RD, Buchbinder S, Cohen D, Colfax G, Da Costa M, Darragh T, Hess E, Judson F, Koblin B, Madison M, Palefsky JM