1. Department of Internal Medicine; Radboud University Medical Centre; Nijmegen the Netherlands
2. Department of Internal Medicine III; University Hospital Carl Gustav Carus; Technical University of Dresden; Dresden Germany
3. Expert Centre for Chronic Fatigue; Radboud University Medical Centre; Nijmegen the Netherlands
4. Centre for Molecular and Biomolecular Informatics; Radboud University Medical Centre; Nijmegen the Netherlands
5. Department of Medical Psychology; Academic Medical Centre (AMC); University of Amsterdam; Amsterdam the Netherlands