Nnaji, Chibueze Eze, Jude O. Chukwu, and Moses Nnaji. 2013. “ Co2 Emissions and Economic Growth: Implications and Policy Options for Sustainable Development in Nigeria”. International Journal of Energy Economics and Policy 3 (3):262-71. https://www.econjournals.com/index.php/ijeep/article/view/465.