Abdullahi, Muhammad Mustapha, et al. “Debt Overhang Versus Crowding Out Effects: Understanding the Impact of External Debts on Capital Formation in Theory”. International Journal of Economics and Financial Issues, vol. 6, no. 1, Jan. 2016, pp. 271-8, https://mail.econjournals.com/index.php/ijefi/article/view/1562.