About: http://webisa.webdatacommons.org/179151472

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	The guide 18 preferably is made from a crystal material such as silicon to allow one to precisely form (e.g., etch) the V-groove surfaces, although it can be made from other materials as well such as glass, polymers, and the like.
http://www.w3.org/ns/prov#wasQuotedFrom	google.es