<http://webisa.webdatacommons.org/313330402>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<google.ca> .
<http://webisa.webdatacommons.org/prov/298706271>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/313330402> .
<http://webisa.webdatacommons.org/313330402>	<http://www.w3.org/ns/prov#value>	"The tube is preferably formed of pyrex glass or other material that is transparent to low-frequency electromagnetic signals, but itself produces little or no low-frequency signal." .
<http://webisa.webdatacommons.org/313330402>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .