1. Ghent University; Department of General Practice and Primary Health Care; 6K3, De Pintelaan 185 Ghent Belgium 9000
2. The University of Queensland; Discipline of General Practice, School of Medicine; Brisbane Queensland Australia 4006
3. Bond University; Centre for Research in Evidence-Based Practice; Gold Coast QLD Australia 4229
4. Georgetown University Medical Center; Department of Family Medicine; 215 Kober Cogan Hall 3750 Reservoir Road, NW Washington DC USA 20007
5. University Hospital Basel; Basel Institute for Clinical Epidemiology; Hebelstrasse 10 Basel Switzerland 4031
6. Ghent University; Heymans Institute of Pharmacology; Ghent Belgium