1. Maastricht University; Department of Clinical Psychological Science ; P.O. Box 616 Maastricht Netherlands 6200 MD
2. Maastricht University; Epidemiology; PO Box 616 Maastricht MD Netherlands 6200
3. Radboud University Nijmegen Medical Centre; Expert Centre for Chronic Fatigue; Mercator 1, Toernooiveld 214 6525 EC Nijmegen HB Netherlands 9101/6500
4. Maastricht University ; Department of General Practice; PO Box 616 Maastricht Netherlands 6200 MD