Aschmann (1993) proposed that the Boran and Witotoan language families were related, in a Bora–Witoto stock. Echeverri & Seifart (2016) refute the connection.
^Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "Boran". Glottolog 3.0. Jena, Germany: Max Planck Institute for the Science of Human History.
Aschmann, Richard P. (1993). Proto Witotoan. Publications in linguistics (No. 114). Arlington, TX: SIL & the University of Texas at Arlington.
Campbell, Lyle. (1997). American Indian languages: The historical linguistics of Native America. New York: Oxford University Press. ISBN0-19-509427-1.
Echeverri, Juan Alvaro & Frank Seifart. (2016). Proto-Witotoan: A re-evaluation of the distant genealogical relationship between the Boran and Witotoan linguistic families.
Kaufman, Terrence. (1990). Language history in South America: What we know and how to know more. In D. L. Payne (Ed.), Amazonian linguistics: Studies in lowland South American languages (pp. 13–67). Austin: University of Texas Press. ISBN0-292-70414-3.
Kaufman, Terrence. (1994). The native languages of South America. In C. Mosley & R. E. Asher (Eds.), Atlas of the world's languages (pp. 46–76). London: Routledge.