* IETF における定義

[1] 
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In the IETF, the term "internationalization" is used to describe
adding or improving the handling of non-ASCII text in a protocol.

;; [CITE@en[RFC 4690 - Review and Recommendations for Internationalized Domain Names (IDNs)]] ([TIME[2011-03-27 16:14:29 +09:00]] 版) <http://tools.ietf.org/html/rfc4690#section-1.5.5>