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) ·

Ethnologue: Languages of the World, 16th Edition (2009) . (2009) · edited by M. Paul Lewis · SIL International http://www.ethnologue.com/

Rapid appraisal and lexicostatistical analysis surveys of Atong, Ambele, and Menka Widikum-Menka Subdivision Momo Division North West Province . Ayotte, Charlene and Ayotte, Michael (2002) · SIL Electronic Survey Reports. 2002-076 http://www.sil.org/silesr/abstract.asp?ref=2002-076