1. Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
2. Amsterdam Rheumatology & Immunology Center, Amsterdam University Medical Centers, Amsterdam, The Netherlands
3. Department of Rheumatology, Zuyderland Medical Center, Heerlen, The Netherlands
4. Rheumatologie im Struenseehaus, Hamburg, Germany
5. Pfizer Inc, Capelle aan den IJssel, The Netherlands
6. Pfizer Inc, Groton, CT, USA
7. Pfizer Inc, New York, NY, USA
8. Department of Rheumatology, Metroplex Clinical Research Center, Dallas, TX, USA
9. Department of Rheumatology, University of Texas Southwestern Medical Center, Dallas, TX, USA