1. Center for Health Services Research in Primary Care, Durham Veterans Affairs Health Care System, and Department of Population Health Sciences, School of Medicine Duke University Durham NC USA
2. Institute of Nursing Science, Department of Public Health, University of Basel, Basel, Switzerland and Division of Gerontology, and Geriatrics, Department of Chronic Diseases Metabolism, and Ageing KU Leuven Leuven Belgium
3. Institute of Nursing Science, Department of Public Health, University of Basel, Basel, Switzerland and Academic Centre for Nursing and Midwifery, Department of Public Health and Primary Care KU Leuven Leuven Belgium