About: http://webisa.webdatacommons.org/183029117

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	But in a small percentage of cases, these headaches can be due to a serious underlying condition, such as a hemorrhage, brain aneurysm, stroke, cervical artery dissection or subdural hematoma.
http://www.w3.org/ns/prov#wasQuotedFrom	medicalxpress.com