Kioko, D. M., and M. Ochieng. “Effect of Portfolio Diversification on the Financial Performance of Investment Firms Listed in the Nairobi Securities Exchange”. Journal of Finance and Accounting, vol. 4, no. 5, Dec. 2020, pp. 77-96, https://stratfordjournalpublishers.org/journals/index.php/journal-of-accounting/article/view/656.