DERAN, A., O. ISKENDEROGLU, and I. ERDURU. “Regional Differences and Financial Ratios: A Comparative Approach on Companies of ISE City Indexes”. International Journal of Economics and Financial Issues, vol. 4, no. 4, Oct. 2014, pp. 946-55, https://www.econjournals.com/index.php/ijefi/article/view/944.