Ayhan Aydın, Abdullah Selvitopu, and Metin Kaya. “Resources Invested in Education and PISA 2015 Results: A Comparative Study ”. Elementary Education Online 17, no. 3 (December 11, 2023): 1283–1301. Accessed December 29, 2024. https://ilkogretim-online.org./index.php/pub/article/view/746.