1. Department of Public Policy, Health Care for the Homeless, 421 Fallsway, Baltimore, MD 21202, USA
2. Department of Emergency Medicine, Georgetown University Hospital/Washington Hospital Center, 110 Irving Street, NW, Washington, DC 20010, USA
3. Department of Emergency Medicine, University of Maryland School of Medicine, 110 South Paca Street, Suite 200, Baltimore, MD 21201, USA