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 Central Africa ( pp. 163-178 ) . Bruce Connell (2007) · In Language Diversity Endangered 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

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

Coastal Bantu of the Cameroons: the Kpe-Mboko, Duala-Limba and Tanga-Yasa groups of the British and French trusteeship territories of the Cameroons ( pp. viii, 116 ) . Ardener, Edwin W. (1956) · Ethnographic survey of Africa, Western Africa, #11 · International African Inst. (IAI)

The noun class system of Kole . Asobo, Irene Swiri (1989) ·

The phonology of Kole . Ewota, James (1973) ·