Risk factors for syphilis infection in men who have sex with men: results of a case–control study in Lille, France
Karen Champenois, Anthony Cousien, Bakhao Ndiaye, Yougoudou Soukouna, Véronique Baclet, Isabelle Alcaraz, Philippe Choisy, Pascal Chaud, Annie Velter, Anne Gallay, Yazdan Yazdanpanah
Sexually Transmitted Infections Mar 2013, 89 (2) 128-132; DOI: 10.1136/sextrans-2012-050523