1. Danish Headache Centre, Department of Neurology, Rigshospitalet Glostrup, Glostrup, Denmark
2. Department of Neurology, Pontificia Catolica University of Chile, Santiago, Chile
3. Foundation of the Valencian Community, University Clinical Hospital, Valencia, Spain
4. Department of Neurology, University of Essen, Essen, Germany
5. Foundation for Combatting Neurological Diseases of Childhood, Buenos Aires, Argentina
6. ISalud University, Buenos Aires, Argentina
7. Headache Science Centre, C. Mondino National Neurological Institute, Pavia, Italy
8. Department of Brain and Behavioral Sciences, University of Pavia, Italy