Bolkol, Hakkı Kutay. “Analysis of Regional Income Convergence in Turkey”. International Journal of Research in Business and Social Science (2147- 4478) 8, no. 2 (March 26, 2019): 01–28. Accessed October 18, 2021. http://ssbfnet.com/ojs/index.php/ijrbs/article/view/198.