title: Epidemiologic clues and the classification of primary headaches.
authors.forename: W F
authors.initials: WF
authors.lastname: Stewart
authors.forename: R B
authors.initials: RB
authors.lastname: Lipton
mesh_terms: D005260:Female; D006261:Headache / Q000145:classification / Q000453:epidemiology*; D006801:Humans; D008297:Male; D015995:Prevalence