1. Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
2. Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
3. Center for Health Services Research in Primary Care, Veterans Affairs Medical Center, Durham, North Carolina.
4. Department of Medicine, Duke University Medical Center, Durham, North Carolina.
5. Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin.
6. Department of Surgery, Gundersen Health System, La Crosse, Wisconsin.
7. William S. Middleton Veterans Affairs Memorial Hospital, Madison, Wisconsin.