Willabo A. Miepamo, et al. “Aquifer Vulnerability Assessment in Ekowe, Bayelsa State, Niger Delta Area, Nigeria Using GIS-Based on Drastic Method”. Journal of Science & Technology (JST), vol. 6, no. 3, May 2021, pp. 37-44, doi:10.46243/jst.2021.v6.i3.pp37-44.