INEGI (Instituto Nacional de Estadística, Geografía e Informática) (1993) La población hablante de lengua indígena en México (XI Censo General de Población y Vivienda, 1990). Aguascalientes: INEGI.
Crevels, Mily. 2012. "Language Endangerment in South America: The Clock Is Ticking." In The Indigenous Languages of South America: A Comprehensive Guide, edited by Hans Henrich Hock et al.. 167-234. Mouton de Gruyter.
Siebert, Ralph, Kati Siebert and Klaus Wedekind. 2002. "Sociolinguistic Survey Report On Languages of the Asosa - Begi - Komosha Area Part I." Online: http://www.sil.org/silesr/2002/SILESR2002-054.pdf.
Adelaar, William and J. Diego Quesada. 2007. "Meso-America." In Encyclopedia of the World's Endangered Languages, edited by Christopher Moseley. 197-209. London and New York: Routledge.
Zelealem Leyew and Ralph Siebert. 2001. "Sociolinguistic Survey Report of the Argobba Language of Ethiopia." SIL International. Online: http://www-01.sil.org/silesr/2002/026/SILESR2002-026.pdf.
Zelealem, [Mollaligne] Leyew. 1995. "Kemant (Qimant): a Language On the Brink of Extinction." In SLLE (Survey of little-known languages of Ethiopia) linguistic reports, 30: 2-30.
Zelealem, [Mollaligne] Leyew. 1994. "First Report On a Survey of the Shinasha and Agew Dialects and Languages." In SLLE (Survey of little-known languages of Ethiopia) linguistic reports, 18: 1-8.