1. The George Washington University, Washington, DC, USA
2. Centers for Disease Control and Prevention, Hyattsville, MD, USA
3. Boston Medical Center, Boston, MA, USA
4. University of Pennsylvania, Philadelphia, PA, USA
5. Yale School of Public Health, New Haven, CT, USA
6. Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
7. Planned Parenthood of Southern New England, New Haven, CT, USA