Abangma, Samson Negbo. 2002. "The Forms and Functions of Questions in Denya." In Journal of West African languages, 29 , no. 2: 49-64.

Abangma, Samson Negbo. 1992. "Empty Categories in Denya."

Abangma, Samson Negbo. 1987. "Modes in Dényá Discourse." xii, 123. Summer Inst. of Linguistics (SIL); Univ. of Texas at Arlington.

Abangma, Samson Negbo. 1981. "The Use of Modes in Denya Discourse: a Study in Discourse Analysis."

[1859]. 1859. "African Discovery." In Journal of the American Geographical and Statistical Soc., 1 , no. 7: 200-201.

Isaac, Kendall and James S. Roberts. 1999. "Sociolinguistic Survey of the Besmé Language of Chad." Association SIL.

Boyeldieu Pascal, 2008, Yulu, La qualification dans les langues africaines / Qualification in African Languages (H. Tröbs, E. Rothmaler & K. Winkelmann éds), Cologne, Rüdiger Köppe Verlag (Topics in African Studies 9), 195-210.

Boyeldieu, Pascal. 1989. "Comparative Tonal Systems: Yulu/Kara Vs Sara Group."

Boyd, Raymond. 2007. "Les Emplois De Certains Morphèmes Déictiques En Bata (Tchadique Centrale)." In Topics in Chadic Linguistics IV: Comparative and Descriptive Studies: Papers from the 3rd Biennial International Colloquium on the Chadic Languages, edited by Henry Tourneux. Köln, 61-86. Rüdiger Köppe Verlag.

Dettweiler, Stephen and Sonia Dettweiler. 2002. "Sociolinguistic Survey of the Pongu People." Online: http://www.sil.org/silesr/2002/SILESR2002-040.pdf.