PELEN, Mustafa Serkan, and Perihan DİNÇ ARTUT. “7TH GRADE STUDENTS’PROBLEM SOLVING SUCCESS RATES ON PROPORTIONAL REASONING PROBLEMS”. The Eurasia Proceedings of Educational and Social Sciences, vol. 2, Sept. 2015, pp. 96-100, https://epess.net/index.php/epess/article/view/103.