About: http://webisa.webdatacommons.org/33516203

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	FIG. 1 is a vertical cross section of a rotating drilling head embodying the invention;
http://www.w3.org/ns/prov#wasQuotedFrom	google.com