“A Comparative Study on the Effect of Combined Methanolic Leaf Extracts of Vernonia amygdalina and Gongronema latifolium and Metformin on the Pancreatic beta cells of Streptozocin Induced Diabetic Wistar Rats”, AJPNMS, vol. 5, no. 2, Apr. 2017, doi: 10.24203/ajpnms.v5i2.4591.