Millett, Gregorio A., John L. Peterson, Stephen A. Flores, Trevor A. Hart, William L. Jeffries, Patrick A. Wilson, Sean B. Rourke, Charles M. Heilig, Jonathan Elford, Kevin A. Fenton et al. "Comparisons of disparities and risks of HIV infection in black and other men who have sex with men in Canada, UK, and USA: a meta-analysis." Lancet 380, no. 9839 (2012): 341-8.