1. Radboud University Nijmegen Medical Centre; Department of General Practice, 117 HAG; P.O. Box 9101 Nijmegen Netherlands 6500 HB
2. Radboud University Medical Centre; Department of General Practice and Family Medicine; 117 Hag PO Box 9101 Nijmegen Netherlands 6500 HB
3. Radboud University Nijmegen Medical Centre ; Department of General Practice, 117 HAG; P.O. Box 9101 Nijmegen Netherlands 6500 HB
4. Radboud University Medical Centre ; Department of General Practice and Family Medicine; 117 Hag P.O. Box 9101 Nijmegen Netherlands 6500 HB
5. University Medical Center Utrecht; Julius Center for Health Sciences and Primary Care; Postbus 85500, Str. 6.131 Utrecht Netherlands 3508 GA
6. Radboud University Nijmegen Medical Centre; Department of General Practice; (117 HAG) PO Box 9101 Nijmegen Netherlands 6500 HB