Persistent Uniform Resource Locator
A Persistent Uniform Resource Locator or PURL is an identifier in the form of a URL that does not refer to an Internet resource, but indirectly to a link resolver, which returns the actual current URL of the resource. From a user perspective, a PURL thus corresponds to an HTTP redirect. PURLs - as URNs - a way consistent, persistent ( = existing remaining ) references to the content of websites provide, while the actual addresses of the pages can remain variable. PURL is managed by the Online Computer Library Center OCLC.
Alternatives to PURL, for example, Digital Object Identifier, the Handle System and Uniform Resource Names.