Anoruo, Emmanuel, and Uchenna Elike. “Human Capital-Economic Growth Nexus in Africa: Heteregeneous Panel Causality Approach”. International Journal of Economics and Financial Issues 5, no. 4 (October 16, 2015): 1017–1023. Accessed April 24, 2024. https://www.econjournals.com/index.php/ijefi/article/view/1473.