بن سعيد آل كحلان ث. and بن محمد موسى محزري إ. (2020) “The effect of using the developed cluster learning strategy in teaching mathematics in high-density classes on academic achievement and mathematical tendencies among middle school students”, Journal of College of Education, 2(40), pp. 413–440. doi:10.31185/eduj.Vol2.Iss40.1622.