A PURL is a Persistent Uniform Resource Locator. Functionally, a PURL is a URL. However, instead of pointing directly to the location of an Internet resource, a PURL points to an intermediate resolution service. The PURL resolution service associates the PURL with the actual URL and returns that URL to the client. The client can then complete the URL transaction in the normal fashion. In Web ...

BNF for specific URL schemes This is a BNF-like description of the Uniform Resource Locator syntax. A vertical line | indicates alternatives, and indicate optional parts. Spaces are represented by the word space , and the vertical line character by vline . Single letters stand for single letters. All words of more than one letter below are entities described somewhere in this description. The ...