Fernández-de-Las-Peñas C, Ortega-Santiago R, Cuadrado ML, López-de-Silanes C, Pareja JA. Bilateral widespread mechanical pain hypersensitivity as sign of central sensitization in patients with cluster headache. Headache. 2011 Mar;51(3):384-91. doi: 10.1111/j.1526-4610.2010.01791.x. PubMed PMID: 21054363.