Headache as the reason for office visits, National Ambulatory Medical Care Survey: United States, 1977-78.
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006261:Headache / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010548:Personal Health Services / Q000706:statistics & numerical data*; D013223:Statistics as Topic; D014481:United States