Bandele, S.O., and A.E. Adewale. “Comparative Analysis of the Item Difficulty Levels of Waec, Neco and Nabteb Mathematics Achievement Examinations”. Mediterranean Journal of Social Sciences 4, no. 2 (May 1, 2013): 761. Accessed March 22, 2023. https://www.richtmann.org/journal/index.php/mjss/article/view/265.