1. Department of Medicine, University of North Carolina at Chapel Hill2RTI International–University of North Carolina at Chapel Hill Evidence-based Practice Center3Cecil G. Sheps Center for Health Services Research, University of North Carolina at Chapel Hill
2. RTI International–University of North Carolina at Chapel Hill Evidence-based Practice Center3Cecil G. Sheps Center for Health Services Research, University of North Carolina at Chapel Hill
3. Department of Medicine, University of North Carolina at Chapel Hill3Cecil G. Sheps Center for Health Services Research, University of North Carolina at Chapel Hill4Now with the Department of Medicine, Northwestern University, Chicago, Illinois
4. RTI International–University of North Carolina at Chapel Hill Evidence-based Practice Center5RTI International, Research Triangle Park, North Carolina6Now with the Center for Cognitive Neuroscience, Duke University, Durham, North Carolina
5. RTI International–University of North Carolina at Chapel Hill Evidence-based Practice Center5RTI International, Research Triangle Park, North Carolina