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) ·

Endangered Languages in West Africa ( pp. 140-162 ch. 7 ) . Roger Blench (2007) · In Language Diversity Endangered Trends in Linguistics, Studies and Monographs · edited by Matthias Brenzinger · Mouton de Gruyter

One Thousand Languages: Living, Endangered, and Lost . Peter Austin (2008) · University of California

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

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

The integrity of Mambiloid ( pp. 197-213 ) . Connell, Bruce A. (2000) · In Proceedings of the 2nd world congress of African linguistics, Leipzig 1997 edited by Wolff, Ekkehard and Gensler, Orin David · Rüdiger Köppe Verlag