Trends in the population prevalence of people who inject drugs in US Metropolitan Areas 1992-2007 - Tempalski, Barbara; Friedman, Samuel R.; West, Brooke S.; Lansky, Amy L.; Hall, H. Irene; Cooper, Hannah L. F.; Brady, Joanne E.; Cleland, Charles M.; Pouget, Enrique R. (PLOS ONE, 2013)