1. Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands;
2. Formerly of the Department of General Practice, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands;
3. Department of Primary and Community Care, Radboud University Medical Centre, Nijmegen, The Netherlands;
4. Australian Primary Health Care Research Institute, Australian National University, Canberra, Australia