1. Montefiore Headache Center; Bronx NY USA
2. Department of Neurology; Montefiore Medical Center, Albert Einstein College of Medicine; Bronx NY USA
3. Department of Neurology; Mayo Clinic; Rochester MN USA
4. The Kaplan Headache Center, Optimum Health Medical Group, PLLC; Clifton Park NY USA
5. Department of Neurology; Medstar Georgetown University Medical Center; Washington DC USA
6. Department of Neurology; University of Michigan Health System; Ann Arbor MI USA
7. Department of Neurology; Yale School of Medicine; New Haven CT USA
8. The Headache Center of Southern California; Encinitas CA USA
9. Pain and Headache Center, Cushing Neuroscience Institute, Department of Neurology, Hofstra North Shore LIJ Medical Center; Manhasset NY USA
10. The Neurology Center; Silver Spring MD USA
11. Department of Neurology; Mayo Clinic; Scottsdale AZ USA
12. Carolina Headache Institute; Durham NC USA
13. Department of Medicine (Neurology); Doylestown Hospital; Doylestown PA USA