Ethnologue: Languages of the World, 18th Edition . (2015) · edited by Lewis, M. Paul, Gary F. Simons, and Charles D. Fennig · SIL International http://www.ethnologue.com

A Survey of the Tonda Sub-Group of Languages . Grummitt, John Janell Masters (2012) · SIL Electronic Survey Report ·

Glottolog 2.3 . Hammarström, Harald & Forkel, Robert & Haspelmath, Martin & Nordhoff, Sebastian (2014) · http://glottolog.org