1. Mayo Clinic, Phoenix, AZ, USA
2. The Geisel School of Medicine at Dartmouth, Hanover, NH, USA
3. Jefferson Headache Center, Philadelphia, PA, USA
4. Mid-Atlantic Permanente Research Institute (Kaiser Permanente Mid-Atlantic States), Rockville, MD, USA
5. Montefiore Headache Center, Albert Einstein College of Medicine, Bronx, NY, USA
6. Stanford Headache Program, Stanford, CA, USA
7. UCLA Headache Research and Treatment Program, Los Angeles, CA, USA
8. NIHR-Wellcome Trust King's Clinical Research Facility, Kings College London, UK
9. UCSF, San Francisco, CA, USA
10. R. P. Chiacchierini Consulting, Gaithersburg, MD, USA