Musa Saheed Ibrahim, Chinwe Christy Isitua, and Thelma Konyeme 2026. Spatial Dispersion of Spent Engine Oil in Soil and Gradient-Dependent Effects on Growth and Physiological Responses of Spinach (Spinacia oleracea L.). Journal of Biological Research and Biotechnology. 24, 2 (Aug. 2026), 598–604. DOI:https://doi.org/10.4314/.