Schuh, Russell G. 1981. A dictionary of Ngizim. Berkeley: University of California Press.

Schuh, Russell. 2009. Yobe Languages Research Project. http://aflang.humnet.ucla.edu/Ngizim/ngizim.html

Connell, Bruce. 1994. The Lower Cross languages: a prolegomena to the classification of the Cross River languages. Journal of West African Languages XXIV. 3-46.

Wannemacher, Mark. 1999. Aspects of Zaiwa prosody: an autosegmental account. (SIL International and the University of Texas at Arlington Publications in Linguistics, vol.129)

Lustig, Anton. 2010. Zaiwa Grammar and Dictionary. Leiden: Brill. (2 vols.)

Shashi, P. and S. S. Shri. 1994. Encyclopedia of Indian tribes. New Delhi: Anmol Publications.

Suantak, Khawlsonkim. 2011. Linguistic Ecology of Vaiphei. In Singh, Shailendra Kumar (ed.), Linguistic Ecology: Manipur, 94-107. Guwahati: EBH Publishers.

Silva, Léia de Jesus. 2010. Diagnóstico sociolinguístico do povo rikbaktsa. (Levantamento realizado no quadro do projeto de documentação da língua rikbaktsa). Rio de Janeiro: Museu do Indio/UNESCO.

Hofling, Charles Andrew. 2007. Notes on Mopan Lexicon and Lexical Morphology. Proceedings of the Conference on Indigenous Languages of Latin America-III. http://www.ailla.utexas.org/site/cilla3/Hofling_CILLA_III.pdf

Richards, Michael. 2003. Atlas Lingüístico de Guatemala. Guatemala: Editorial Serviprensa,