1. Centers for Disease Control and Prevention (US) (2016) National hospital ambulatory medical care survey: 2016 emergency department summary tables. Available at https://www.cdc.gov/nchs/data/nhamcs/web_tables/2016_ed_web_tables.pdf
2. Koyfman A, Long B (2020) Headache. In: Tintinalli JE, Ma OJ, Yealy DM, Meckler GD, Stapczynski JS, Cline DM, Thomas SH (eds) Tintinalli’s emergency medicine: a comprehensive study guide, 9th edn. McGraw-Hill, New York, pp 1107–1114
3. Russi CS, Headache WL (2018) In: Walls RM, Hockberger RS, Gausche-Hill M et al (eds) Rosen’s emergency medicine: concepts and clinical practıce, 9th edn. Elsevier, Philadelphia, pp 153–159
4. Singer RJ, Ogilvy CS, Rordorf G (2021) Aneurysmal subarachnoid hemorrhage: clinical manifestations and diagnosis. In: Goddeau RP, Biller J, Rabinstein AA, Edlow JA (eds) UpToDate. Available at https://www.uptodate.com/contents/aneurysmal-subarachnoid-hemorrhage-clinical-manifestations-and-diagnosis
5. Singer RJ, Ogilvy CS, Rordorf G (2022) Aneurysmal subarachnoid hemorrhage: epidemiology, risk factors, and pathogenesis. In: Goddeau RP, Biller J (ed) UpToDate. Available at https://www.uptodate.com/contents/aneurysmal-subarachnoid-hemorrhage-epidemiology-risk-factors-and-pathogenesis