1. Amha, A. (2012). Omotic. In Z. Frajzyngier, & E. Shay (pp. 423–504).
2. Atiya, A. S. (Ed.). (1991). The Coptic encyclopedia. Macmillan.
3. Bender, M. L. (1971). The languages of Ethiopia: A new lexicostatistic classificatin and some problems of diffusion. Anthropological Linguistics, 13(5), 165–288.
4. Committee on Ethiopian studies occasional papers series 5;ML Bender,1976
5. LINCOM handbooks in linguistics 06;ML Bender,1997