Molindo, W., Usifo, A., & Akoma, O. (2009). Physico-chemical Analysis of an Ultisol Polluted with Different Petroleum Products Treated with Poultry Droppings and Planted with Maize in Benin City, Nigeria. Ethiopian Journal of Environmental Studies and Management, 2(2). https://doi.org/10.4314/ejesm.v2i2.45920