1. Department of Rheumatology, Internal Medicine III, Medical University of Vienna Austria,
2. Department of Rheumatology, Internal Medicine III, Medical University of Vienna Austria, ICF Research Branch of the WHO Collaborating Center for the Family of International Classifications at the German Institute of Medical Documentation and Information (DIMDI), IMBK, Munich, Germany, Department of Physical Medicine and Rehabilitation, Ludwig-Maximilians-University, Munich, Germany
3. Medical Research Service, Durham VA Hospital, Durham, NC, USA, Division of Rheumatology and Immunology, Duke University Medical Center, Durham, NC, USA
4. National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD, USA
5. ICF Research Branch of the WHO Collaborating Center for the Family of International Classifications at the German Institute of Medical Documentation and Information (DIMDI), IMBK, Munich, Germany
6. Department of Rheumatology, Internal Medicine III, Medical University of Vienna Austria, Department of Medicine II, Lainz Hospital, Vienna, Austria
7. ICF Research Branch of the WHO Collaborating Center for the Family of International Classifications at the German Institute of Medical Documentation and Information (DIMDI), IMBK, Munich, Germany, Department of Physical Medicine and Rehabilitation, Ludwig-Maximilians-University, Munich, Germany