Basal, A., K. M. Celen, H. Kaya, and Şeyma N. Boğaz. “An Investigation into Ilustrations in English Course Books in a Turkish Context”. International Electronic Journal of Elementary Education, vol. 8, no. 3, Aug. 2017, pp. 525-36, https://iejee.com/index.php/IEJEE/article/view/129.