Property:Equivalent URI
[http://www.nga.gov/content/ngaweb/research/casva/research-projects.html A Project of the National Gallery of Art, Center for Advanced Study in the Visual Arts ]
"Equivalent URI" is a type and predefined property provided by Semantic MediaWiki to represent URI/URL values. This property is pre-deployed (also known as special property) and comes with additional administrative privileges but can be used just like any other user-defined property.