| Affiliation: | 1. Department of Family Medicine, University of North Carolina School of Medicine, CB# 7595, Chapel Hill, NC 27599-7595, USA;2. Injury Prevention Research Center, CB# 7505, University of North Carolina, Chapel Hill, NC, USA;3. Department of Medicine, Division of General Medicine and Epidemiology, University of North Carolina School of Medicine, 5039 Old Clinic Building, CB# 7110, Chapel Hill, NC 27599-7110, USA;4. Beacon Child and Family Program, CB# 7600, University of North Carolina School of Medicine, Chapel Hill, NC 7595-7600, USA |
