Africa ( ch. 7 ) . Gerrit J. Dimmendaal and F. K. Erhard Voeltz (2007) · In Encyclopedia of the World's Endangered Languages edited by Christopher Moseley · Routledge

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