Atlas of the World’s Languages in Danger . Christopher Moseley (ed.) (2010) · UNESCO Publishing http://www.unesco.org/culture/en/endangeredlanguages/atlas

ISO 639-3 Language Code Request for Jejueo . William O'Grady and Changyong Yang and Sejung Yang (2014) · http://www-01.sil.org/iso639-3/cr_files/2014-004_jje.pdf