Ninu iyasoto àwọn èdè Áfríkà, awon ede Volta-Kóngò lopojulo ninu awon ede ibatan Atlántíkì-Kóngò, pelu awon sistemu ikosoto oro-oruko to wopo ninu awon ede Àwọn èdè Atlántíkì-Kóngò. Casali, Roderic F. (1995) 'On the Reduction of Vowel Systems in Volta–Congo', African Languages and Cultures, 8, 2, Dec, 109–121. Stewart, John M. (1976) Towards Volta–Congo reconstruction: a comparative study of some languages of Black-Africa. (Inaugural speech, Leiden University) Leiden: Universitaire Pers Leiden. Stewart, John M. (1985) 'Nasality patterns in the Volta–Congo foot.' Paper presented at the Colloquium on African Linguistics, Leiden, Sept. 1985. Williamson, Kay & Blench, Roger (2000) 'Niger–Congo', in Heine, Bernd and Nurse, Derek (eds) African Languages — An Introduction. Cambridge: Cambridge University press, pp. 11–42.