1. Norwegian University of Science and Technology; Department of Neuroscience; Trondheim Norway
2. St. Olav’s University Hospital; Norwegian Advisory Unit on Headaches; Trondheim Norway
3. Canisius Wilhelmina Ziekenhuis; Department of Neurology; PO Box 9015 Nijmegen Netherlands 6500 GS
4. University of Hawaii at Manoa; (Deceased) Department of Psychology; Manoa USA
5. Duke University Medical Center; Department of Medicine; Durham NC USA 27710
6. Durham Veterans Affairs Medical Center; Center for Health Services Research in Primary Care; 508 Fulton St Durham NC USA 27705