1. Department of Neurology, Danish Headache Center, Rigshospitalet, Glostrup, 2600, Denmark
2. Faculty of Health & Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
3. Teva Netherlands B.V., BR, Amsterdam, 1019, The Netherlands
4. Teva Branded Pharmaceutical Products R&D, Inc., West Chester, PA 19380, USA
5. Department of Brain & Behavioral Sciences, University of Pavia, Pavia, 27100, Italy
6. Headache Science & Neurorehabilitation Center, IRCCS Mondino Foundation, Pavia, 27100, Italy
7. Department of First Neurology, Aeginition Hospital, Medical School, National & Kapodistrian University of Athens, Athens, 11528, Greece