About: http://webisa.webdatacommons.org/367003917

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	distance (3 feet) to prevent accidental falls through the opening and to prevent tools and other items
http://www.w3.org/ns/prov#wasQuotedFrom	docstoc.com