1. Jadin, L., and M. Dicorato. 1974. Correspondance de Dom Afonso, roi du Congo, 1506–1543. Bruxelles: ARSMP.
2. Nooter, P.N., ed. 1993. Secrecy: African art that conceals and reveals. New York/Munich: The Museum for African Art-Prestel.
3. Parkin, D. 1991. The sacred void: Spatial images of work and rituals among the Giriama of Kenya. New York: Cambridge University Press.
4. Roy, C. 1987. Art in the upper Volta Rivers. Paris: Alain et Françoise Chafin.
5. Turner, V.W. 1968. Drums of affliction: A study of religious process among the Ndembu of Zambia. Oxford: Clarendon Press.