1968. "Benue-Congo Comparative Wordlist." edited by Kay Williamson and Kiyoshi Shimizu. I: 233. University of Ibadan, Nigeria: West African Linguistic Society.
Kay Williamson. 2000. "Towards Reconstructing Proto-Niger-Congo." In Proceedings of the 2nd World Congress of African Linguistics: Leipzig 1997, edited by H. Ekkehard Wolff and Orin D. Gensler. 49-70. Köln: Rüdiger Köppe.
Williams, G. 1994. "Intelligibility and Language Boundaries Among the Cangin Peoples of Senegal." In Journal of West African Languages, XXIV , no. 1: 47-67.
Wiedemann, Sabine and Prossy Nannyombi. 2007. "Ik Language Assessment Report: Kaabong District Uganda." In SIL Electronic Survey Reports, 2007-024: Online: http://www.sil.org/silesr/abstract.asp?ref=2007-024.