Authentication and versions...of legal material

From an interview with Margaret Maes on the Library of Congress's Digital Preservation website

"Part of authentication is having the right versions – and all of the versions – of something that you might need if you are a researcher and you are really trying to nail down a point," Maes said. As a law develops from a proposal to a final version, there are often elements of meaning or intent that somebody can use when trying to prove a point about a piece of legislation. In the legal discipline, the more people pay attention to versions, the more important it becomes to preserve them.

Amen to that. That is why we will be ingesting complete temporal databases of complete legislative biennia as SIPs in the KEEP archive.