Internationalized Resource Identifiers (IRIs) - Server-side Implementation

Internationalizing Domain Names in Applications (IDNA), RFC 3490
Uniform Resource Identifiers (URI), RFC 2396 (replaces RFC 1808 and 1738)
Preparation of Internationalized Strings ("stringprep"), RFC 3454
Nameprep: A Stringprep Profile for Internationalized Domain Names (IDN), RFC 3491
Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA), RFC 3492
Unicode Normalization, Normative Technical Report: http://www.unicode.org/unicode/reports/tr15/
W3C Character Model, Working Draft: http://www.w3.org/TR/charmod/
Internationalized Resource Identifiers (IRI): draft: http://www.w3.org/International/iri-edit/draft-duerst-iri.txt
Much simpler module: http://kle.kldp.org/apache/mod_url-apache2.c by Won-kyu Park (base) and JoungKyun Kim

References