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One wiki implementation which supports this type of permalinks is MediaWiki, the software which runs Wikipedia.

In its current implementation, old revisions of specific articles, images, and templates are referenceable by unique unchanging URLs, although old versions of images and templates may not be utilized by current entries.

Permanent links to specific versions are recommended for citing articles from sources such as Wikipedia and Wikinews, to ensure that the content remains unchanged for review.

A reviewer can then view the cited revision, the current revision, and the differences between the two.