Endangered Languages Catalogue Project. Compiled by research teams at University of Hawai'i Mānoa and Institute for Language Information and Technology (LINGUIST List) at Eastern Michigan University . (2012) ·

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

Ethnologue: Languages of the World, 16th Edition (2009) . (2009) · edited by M. Paul Lewis · SIL International http://www.ethnologue.com/

Kra or Kadai languages ( pp. 653-671 ) . Edmondson, Jerold A. (2008) · In The Tai-Kadai Languages edited by Anthony V. N. Diller et al. · Routledge