As national bibliographies are going more and more online, the issue of permanent identifiers for citation and linking is becoming crucial at the international level.
Persistent identifiers are identifiers that can be cited to retrieve digital objects over a long period of time.
Examples of persistent identifier systems include:
- Archival Resource Keys (ARKs)
- Digital Object Identifiers (DOIs)
- Persistent Uniform Resource Locators (PURLs)
- Uniform Resource Names (URNs)
- Extensible Resource Identifiers (XRIs)
More information can be found in the section on Standards