About: http://webisa.webdatacommons.org/239272029

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	In most cases, air and gases such as carbon dioxide and nitrogen generated in situ are adequate to effect echogenicity enhancement and offer low cost and simplicity of manufacture.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com