Mehmet İhsan Yurtyapan, İlhan Karataş. An Investigation of Pedagogical Content Knowledge of Secondary School Mathematics Teachers in Relation with Triangle and Quadrilateral Concepts. TURCOMAT [Internet]. 2020Apr.30 [cited 2024May4];11(1):53-90. Available from: https://turcomat.org/index.php/turkbilmat/article/view/225