1. University of Southern Denmark, Odense, Denmark, and Vejle HospitalHospital Lillebælt Vejle Denmark
2. Nordic Institute of Chiropractic and Clinical Biomechanics, Odense, Denmark, and Silkeborg Regional Hospital Silkeborg Denmark
3. Hospital Lillebaelt, Middelfart, Denmark, and University of Southern Denmark Odense Denmark
4. Rigshospitalet Glostrup, Glostrup, Denmark, and University of Copenhagen Copenhagen Denmark
5. University of Southern Denmark, Odense, Denmark, and King Christian 10th Hospital for Rheumatic Diseases and Hospital of Southern Jutland Gråsten Denmark
6. Aarhus University Hospital Aarhus N Denmark
7. Hospital Lillebaelt, Middelfart, Denmark, University of Southern Denmark, Odense, Denmark, and Aarhus University Hospital and Aarhus University Aarhus N Denmark