1. Department of Haematology; VU University Medical Center; Postbus 7057 1007 MB Amsterdam the Netherlands
2. Department of Internal Medicine; Medical Center Alkmaar; Alkmaar the Netherlands
3. Department of Clinical Psychology; University of Amsterdam; Amsterdam the Netherlands
4. Department of Statistics; Medical Center Alkmaar; Alkmaar the Netherlands
5. Department of Clinical Psychology; VU University; Amsterdam the Netherlands