1. Department of Neurology, Albert Einstein College of Medicine, New York
2. The New England Center for Headache, Stamford
3. Department of Neurology, Columbia University College of Physicians and Surgeons, New York
4. Department of Psychiatry, New York Medical College, New York
5. Department of Neurology, Yale University School of Medicine, New Haven
6. Department of Epidemiology and Social Medicine, Albert Einstein College of Medicine, New York, USA