Sandø, Niels, Kristian Kofoed, Claus Zachariae, and Jan Fouchard. 2013. “A Reduced National Incidence of Anogenital Warts in Young Danish Men and Women After Introduction of a National Quadrivalent Human Papillomavirus Vaccination Programme for Young Women--an Ecological Study”. Acta Dermato-Venereologica 94 (3):288-92. https://doi.org/10.2340/00015555-1721.