The Lisbon Cohort of men who have sex with men
Paula Meireles, Raquel Lucas, Ana Martins, Ana Cláudia Carvalho, Ricardo Fuertes, João Brito, Maria José Campos, Luís Mendão, Henrique Barros
BMJ Open May 2015, 5 (5) e007220; DOI: 10.1136/bmjopen-2014-007220