Monitoring the scale-up of antiretroviral therapy programmes: Methods to estimate coverage

J. Ties Boerma, Karen A. Stanecki, Marie Louise Newell, Chewe Luo, Michel Beusenberg, Geoff P. Garnett, Kirsty Little, Jesus Garcia Calleja, Siobhan Crowley, Yong Kim Jim, Elizabeth Zaniewski, Neff Walker, John Stover, Peter D. Ghys