The hepatitis C epidemic among HIV-positive MSM: incidence estimates from 1990 to 2007 - van der Helm, Jannie J; Prins, Maria; Del Amo, Julia; Bucher, Heiner C; Chene, Genevieve; Dorrucci, Maria; Gill, John; Hamouda, Osamah; Sannes, Mette; Porter, Kholoud; others (Aids, 2011)