Mitsikostas, D.D. Blease, C. Carlino, E. Colloca, L. Geers, A.L. Howick, J. Evers, A.W.M. Flaten, M.A. Kelley, J.M. Kirsch, I. Klinger, R. Maassenvandenbrink, A. Moerman, D.E. Sfikakis, P.P. Vase, L. Wager, T.D. Benedetti, F., European Headache Federation recommendations for placebo and nocebo terminology, The Journal of Headache and Pain, (21), 2020, BioMed Central Ltd., 1129-2369, 1129-2377