1. Sint Maartenskliniek; Nijmegen The Netherlands
2. VU University Medical Center; Amsterdam The Netherlands
3. Leiden University Medical Center; Leiden The Netherlands
4. Dutch Patient Organization for Rheumatic Diseases; Amersfoort The Netherlands
5. University Medical Center; Utrecht The Netherlands
6. Radboud University Nijmegen Medical Center; Nijmegen The Netherlands
7. Erasmus University Medical Center; Rotterdam The Netherlands