1. Thomas Jefferson University, USA
2. Mayo Clinic, USA
3. Michigan Head Pain & Neurological Institute, USA
4. Duke University, USA
5. University of Illinois/Chicago, USA
6. Reed Migraine Centers, USA
7. Summa Western Reserve Hospital, USA
8. NYU Langone Medical Center, USA
9. San Francisco Headache Clinic, USA
10. The Pain and Wellness Center, Peabody, USA
11. Sutter Pacific Medical Foundation, San Francisco, USA
12. The Center for Pain Relief, Charleston, USA
13. University of Florida College of Medicine – Jacksonville, USA
14. St. Jude Medical Neuromodulation, USA
15. Cleveland Clinic, USA