1. Yale School of Medicine, New Haven, CT, USA
2. Fair Haven Community Health Care, New Haven, CT, USA
3. Brown University School of Public Health, Providence, RI, USA
4. Center on Drug and Alcohol Research, Department of Behavioral Science, University of Kentucky College of Medicine, Lexington, KY, USA
5. University of Kentucky College of Public Health, Lexington, KY, USA
6. VA Connecticut Healthcare System, West Haven, CT, USA
7. Center for Health Services Research, Institute for Health, Rutgers University, Rutgers, NJ, USA
8. London School of Hygiene and Tropical Medicine, London, UK
9. Center for Interdisciplinary Research on AIDS, Yale School of Public Health, New Haven, CT, USA