Agbede, T. , Adekiya, A.. "Effects of Sole and Integrated Application of Cocoa Pod Ash and Poultry Manure on Soil Properties and Leaf Nutrient Composition and Performance of White Yam". World Academy of Science, Engineering and Technology, Open Science Index 113, International Journal of Agricultural and Biosystems Engineering (2016), 10(5), 281 - 288.