About: http://webisa.webdatacommons.org/4452921

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	U.S. Pat. No. 7,216,727 to Wardley discloses a casing drilling bit constructed from a relatively soft material such as aluminum, copper, or brass alloy and is coated with relatively hard material.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com