1. The Headache Center of Southern California - Neurology; Encinitas; CA; USA
2. Doylestown Hospital; Doylestown; PA; USA
3. Headache Clinic at Middletown Medical; Middletown; NY; USA
4. North Texas Center for Head; Face & TMJ Pain; Texas A&M University, Baylor College of Dentistry; Plano; TX; USA
5. Abington Headache Center - Neurology; Warminster; PA; USA
6. Albert Einstein College of Medicine/Montefiore Medical Center; Bronx; NY; USA
7. Department of Neurology; Georgetown University Hospital; Washington; DC; USA
8. Departments of Neurology & Neurotherapeutics and Ophthalmology; University of Texas Southwestern Medical Center; Dallas; TX; USA
9. Thomas Jefferson University - Neurology; Philadelphia; PA; USA
10. Neurology Department; Mayo Clinic; Rochester; MN; USA
11. Neurology; Mayo Clinic; Scottsdale; AZ; USA