- Correspondence to Mariam Fofana, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 1830 E. Monument St, Suite 2-300, Baltimore, MD 21205, USA;
- Accepted August 12, 2013
- First published August 29, 2013.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.