Digital Identifiers

LC documents on URNs
This paper discusses current approaches used in American Memory for identifying digital reproductions and gives a general discussion of URLs and URNs. There is also information on how to keep URLs persistent, a discussion on PURLs and handles, and an overview of the handle system developed by CNRI to support a system of global identifiers for resources on the Internet.

PADI
More information on URNs and URLs from PADI--Preserving Access to Digital Information.