1. Department of Neurology, Zealand University Hospital, Roskilde, Denmark
2. Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
3. Pain & Research Department, Rehabilitation Center ZURZACH Care, Bad Zurzach, Switzerland
4. Department of Neurology, University Hospital Zurich, Zurich, Switzerland
5. Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
6. Department of Neurology, Tartu University Hospital, Tartu, Estonia
7. Neurology Clinic, University of Tartu, Tartu, Estonia
8. Headache and Facial Pain Group, The National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, UK
9. Leiden Headache Center, Leiden University Medical Center, Leiden, Netherlands
10. Headache and Facial Pain Group, University College London, Queen Square Institute of Neurology, London, UK
11. The National Hospital for Neurology and Neurosurgery, London, UK
12. Region Värmland, Neurologi- Och Rehabiliteringsmottagningen, Centralsjukhuset, Karlstad, Sweden
13. Máxima Medisch Centrum Location Eindhoven, Netherlands
14. Department of Neurology, Bispebjerg Hospital, Denmark
15. Neurorehabilitation Department, Rehaklinik Bad Zurzach, Switzerland
16. Norwegian Advisory Unit on Headaches, St. Olav University Hospital, Trondheim, Norway
17. NorHEAD, Norwegian Headache Research Centre, Norway
18. Department of Neuromedicine and Movement Science, NTNU, Trondheim, Norway
19. Department of Neurology, Odense University Hospital, Odense, Denmark
20. Neurology Department, Beaumont Hospital, Dublin, Ireland
21. Neurocenter, Helsinki University Hospital, Neurology Outpatient Clinic & Helsinki Headache Center, Helsinki, Finland
22. Department of neurology, St Olav University hospital, Norwegian Headache Research Centre (Norhead), Norwegian University of Science and Technology (NTNU), Trondheim, Norway
23. Unit for Health Promotion Research, University of Southern Denmark, Denmark
24. Research Unit of Neurology, University Hospital of Southern Denmark, Esbjerg, Denmark
25. Department of Regional Health Research, University of Southern Denmark, Odense, Denmark