Primary headache: Causes and consequences. Portuguese Journal of Family Medicine and General Practice, [S. l.], v. 22, n. 4, p. 455–9, 2006. DOI: 10.32385/rpmgf.v22i4.10266. Disponível em: https://rpmgf.pt/ojs/index.php/rpmgf/article/view/10266. Acesso em: 17 apr. 2026.