Abanuka, B. (1994). A new essay on African philosophy. Onitsha: Spiritan Publications.
 Achebe, C. (1978). Things fall apart. London: Heinemann.
 Anyanwu, C. (1988). The meaning of ultimate reality in Igbo cultural experience, in Ultimate reality and meaning (pp. 84-101).
 Chukwuelobe, M. (1995). Language and Igbo philosophy: Towards an Igbo Phenomenology of language in Philosophy Today (pp. 25-30).
 Egbujie, I. (1976). The hermeneutics of African traditional culture. Ph.D. Dissertation, Boston: Boston College.
 Eliade, M. (1959). The sacred and the profane Tr. Willard R. Trask. New York: Harcourt, Brace and Company.
 Eliade, M. (1976). Occultism, witchcraft, and cultural fashions. Chicago: The University of Chicago Press.
 Heidegger, M. (1962). Being and time. Tr. John Macquarrie & Edward Robinson. New York: Harper & Row, Publishers.
 Leonard, A. (1968). The lower niger and its tribes. London: Frank Cass.
 Mbiti, J. (1976). African religions and philosophy. London: Heinemann.
 Nwoga, D. (1984). Nka na nzere: The focus of Igbo world. Ahiajoku Lecture, Owerri: Culture Division, Ministry of Information, Culture, Youth and Sports.
 Ozumba, G. (2001). African traditional metaphysics in Quodlibet Journal (pp. 2-20).
 Shelton, A. J. (1968). Causality in African thought: Igbo and others. Practical Anthropology, 15, 157-169.
 Zahan, D. (1979). The religion, spirituality, and thought of traditional Africa. Tr. K. Ezra and L. Martin. Chicago: University of Chicago Press.