Bukar, A., Isa, M., Bello, H., & Abdullahi, A. (2013). Antibacterial Activityof Aqueous And Ethanolic Leaf Extracts Of Vernonia Amygdalina On Selected Species Of Gram Positive And Gram Negative Bacteria. International Journal of Environment, 2(1), 147–152. https://doi.org/10.3126/ije.v2i1.9217