International African Institute, International Institute of African Languages and Cultures, Westermann, D., Smith, E. W., & Forde, C. D. Africa. Oxford University Press.

International African Institute, International Institute of African Languages and Cultures, Diedrich Westermann, Edwin William Smith, and Cyril Daryll Forde. Africa. London: Oxford University Press.

International African Institute, et al. Africa. Oxford University Press.