Martin J. Dürst, James Seng, Tim Tan:UTF-5, a transformation format of Unicode and ISO 10646. draft-jseng-utf5-02. Internet Engineering Task Force, 28.Januar 2000 (ietf.org[abgerufen am 23.April 2025]).
Mark Welter, Brian Spolarich:UTF-6 – Yet Another ASCII-Compatible Encoding for IDN. draft-ietf-idn-utf6-00. Internet Engineering Task Force, 21.November 2000 (ietf.org[abgerufen am 23.April 2025]).
RFC: 4042– UTF-9 and UTF-18 Efficient Transformation Formats of Unicode.1.April 2005(englisch).