Usunomena, U. ., E. M. . Ewaen, and E. . Kevin. “Comparative in Vitro Antioxidant Activity of Ethanol Extracts of Vernonia Amygdalina and Annona Muricata Leaves”. Nigerian Journal of Pharmaceutical and Applied Science Research, vol. 6, no. 1, Aug. 2020, pp. 37-42, http://mail.nijophasr.net/index.php/nijophasr/article/view/163.