<http://webisa.webdatacommons.org/328918912>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/prov/51040326>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/328918912> .
<http://webisa.webdatacommons.org/328918912>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<qualityhealth.com> .
<http://webisa.webdatacommons.org/328918912>	<http://www.w3.org/ns/prov#value>	"However, according to experts, there are several kinds of headaches, each of which can have a different set of causes, risk factors, and severity levels." .