NOTE: The following links are solely meant to be representative of the intellectual diversity of the sites one can find using a standard search engine. You are urgently advised to read the Fine Print above, especially the section - NO WEB SITE IS A SUBSTITUTE FOR RELIABLE RESEARCH STRATEGIES. The savvy user will then go on to learn how to exploit the ADVANCED capabilities of search engines like HotBot & Google, especially the use of their Exact Phrase & Domain Limiter options. I also highly recommend using XRefer. Among its excellent information resources, it uses the The Oxford Companion to Philosophy, one of the very best reference works for the discipline. What you find in this way can only supplement what you should find after careful research using standard scholarly data bases.
Provisional Bibliography: E.B. Idowu - Olodumare: God in Yoruba Belief; W. Bascom - Ifa Divination; A. Shelton - The Meaning and Method of Ifa Divination; M. Gluckman - Closed Systems and Open Minds; Robin Horton - Patterns of Thought in Africa and the West; J. Vansina - The Oral Tradition: A Study in Historical Methodology; R. Finnegan - Attitudes to the Study of Oral Literature; Godfrey Lienhardt - Divinity and Experience: The Religion of the Dinka; F.A. Arinze - Sacrifice in Igbo Religion; Lucien Lévy-Bruhl - Primitive Mentality [Compiled by E.C. Eze, Bucknell University].