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

A survey on language death in Africa ( pp. 402 ) . Sommer, Gabriele (1992) · In Language death: factual and theoretical explorations with special reference to East Africa Contributions to the sociology of language, #64 · edited by Brenzinger, Matthias · Mouton de Gruyter

An Atlas of Nigerian Languages . Roger Blench (2011) · Mallam Dendo http://www.rogerblench.info/Language/Africa/Nigeria/Atlas%%20of%%20Nigerian%%20Languages-%%20ed%%20III.pdf