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) ·

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

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

World Oral Literature Project . http://www.oralliterature.org

Enquête sociolinguistique de la langue Koulfa du Tchad (rapport technique) . Marti Marianne (2012) · SIL electronic survey reports (SILESR) · http://www.sil.org/silesr/2012/silesr2012-022_FINAL.pdf