RFC 1631: The IP Network Address Translator (NAT)
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This memo proposes another short-term solution, address reuse, that complements CIDR or even makes it unnecessary. The address reuse solution is to place Network Address Translators (NAT) at the borders of stub domains. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.

From the conclusion:

NAT may be a good short term solution to the address depletion and scaling problems. This is because it requires very few changes and can be installed incrementally. NAT has several negative characteristics that make it inappropriate as a long term solution, and may make it inappropriate even as a short term solution. Only implementation and experimentation will determine its appropriateness.