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

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

An introduction to the Mambiloid languages ( pp. 79-92 ) . Connell, Bruce A. (2001) · In Research mate in African linguistics (focus on Cameroon): a fieldworker’s tool for deciphering the stories Cameroonian languages have to tell, in honor of Professor Larry M. Hyman Grammatische Analysen afrikanischer Sprachen, #17 · edited by Mutaka, Ngessimo M. and Chumbow, Beban Sammy · Rüdiger Köppe Verlag