ISO-3166-1

A document maintained by the International Standards Organization that gives coded representations of more than 230 names of countries or areas independent from countries. This document contains two-letter (Alpha-2-code), a three-letter code (Alpha-3-code) and a three-digit numeric code (Numeric-3-code) for every entry in its list of country names. This was typically the document that IANA used to create ccTLD entries in the root-zone system.