1. a Center for Health Services Research in Primary Care, Durham VAMC and Department of Medicine, Division of General Internal Medicine, Duke University Medical Center, Durham, North Carolina, USA
2. e University of Minnesota, Minneapolis, USA
3. b Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
4. c The Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon, USA
5. d National Cancer Institute, Bethesda, Maryland, USA