Uysal, Sengul, and Koksal Banoglu. “Hogging the Middle Lane: How Student Performance Heterogeneity Leads Turkish Schools to Fail in PISA?”. Cypriot Journal of Educational Sciences 13, no. 2 (June 26, 2018): 201–213. Accessed May 19, 2024. https://www.un-pub.eu/ojs/index.php/cjes/article/view/3196.