1. Headache Science Centre, IRCCS Mondino Foundation, Pavia, Italy
2. Department of Brain and Behavioral Sciences, University of Pavia, Italy
3. Department of Neurology, Pontificia Catolica University of Chile, Santiago, Chile
4. Department of Neurology, University of Essen, Germany
5. Foundation of the Valencian Community, University Clinical Hospital, Spain
6. Integral Pain Centre, Fundación para la Lucha contra las Enfermedades Neurológicas Infantiles (FLENI), Buenos Aires, Argentina
7. Danish Headache Centre, Department of Neurology, Glostrup Hospital, Glostrup, Denmark