1. Center for General Practice, Aalborg University, Fyrkildevej 7, DK-9200 Aalborg Ø, Denmark
2. The Research Unit and Section of General Practice, Department of Public Health, University of Copenhagen, Ø. Farimagsgade 5,opg.Q, DK-1014 Copenhagen, Denmark
3. Hovedgaden 43, DK-2970 Hoersholm, Denmark
4. Research Unit of General Practice, Southern University, J. B. Winsløvs Vej 9A, DK-5000 Odense, Denmark