H.M Zaki, N, M Mustaffa, M F.M. Taib, O H.Hassan, M Z.A.Yahya, and A M.M.Ali. 2018. “Understanding the Electronic Transition of Normal Spinel Structure of Co3O4 Using GGA+U Calculations”. International Journal of Engineering and Technology 7 (3.11): 121-25. https://doi.org/10.14419/ijet.v7i3.11.15943.