1. Department of Neurology and Headache Centre, Hospital ‘G. Rummo’ Benevento, Benevento, Italy
2. Departments of Neurology, Albert Einstein College of Medicine
3. Departments of Epidemiology and Population Health, Albert Einstein College of Medicine
4. Montefiore Headache Unit, Bronx, NY
5. The New England Center for Headache, Stamford, CT
6. Department of Neurology, Columbia University College of Physicians & Surgeons, New York, NY, USA