About: http://webisa.webdatacommons.org/420622842

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	Researchers at Harvard Women???s Health Watch aren???t certain what causes such headaches, but they suspect changes in blood vessels and muscles that occur naturally during sexual activity are a factor.
http://www.w3.org/ns/prov#wasQuotedFrom	shsu.edu