Kang, B.T. and Mulongoy, K. (1992) Nitrogen Contribution of Woody Legumes in Alley Cropping Systems. In: Mulonogy, K., Gueye, M. and Spencer, D.S.C., Eds., Biological Nitrogen Fixation and Sustainability of Tropical Agriculture, Wiley, Hoboken, 367-375.
 Agboola, D.A. (1991) The Effects of Soil Types and pH on the Germination of Seeds of Some Tropical Forest Tree Species. 5th Annual Conference of the Botanical Society of Nigeria, Ile-Ife, 24-28 March 1991, 20-37.
 Agboola, A.A. and Unamma, P.A. (1991) Maintenance of Soil Fertility under Traditional Farming System. Proceedings of the National Organic Fertilizer Seminar held in Kaduna, Abuja, 12-16 September 1991, 7-20.
 Aweto, A.O. (1981) Secondary Succession and Soil Fertility Restoration in South-Western Nigeria. I. Succession. Journal of Ecology, 69, 601-607.
 Aweto, A.O (1981) Secondary Succession and Soil Fertility Restoration in South-Western Nigeria. II. Soil Fertility Restoration. Journal of Ecology, 69, 609-614.
 Attah-Krah, A.N. (1990) Alley farming with Leucaena: Effect of Short Grazed Fallows on Soil Fertility and Crop Yields. Experimental Agriculture, 26, 1-10.
 Ande, O.T., Adediran, J.A., Ayoola, O.T. and Akinlosolu, T.A. (2008) Effects of Land Quality, Management and Cropping Systems on Cassava Production in South-Western Nigeria. African Journal of Biotechnology, 17, 2368-2374.
 Murdoch, G., Atere, J.O., Colborne, G., Olomu, E.I. and Odugbesan E.M. (1976) Soils of the Western State Savanna in Nigeria. Land Resources Div., Ministry of Overseas Development, Tolworth, Surbitton, Surrey, 3-11
 Nwanchokor, M.A. and Nzu, F.O. (2008) Updated Classification of Some Soils Series in South Western Nigeria. Journal of Agronomy, 7, 76-81.
 Bouyoucous, G.J. (1951) A Recalibration of the Hydrometer for Making Mechanical Analysis of Soils. Agronomy Journal, 43, 434-438.
 Bray, R.N. and Kurtz, L.T. (1945) Determination of the Organic and Available Forms of Phosphorus in Soil. Soil Science, 59, 39-45.