1. A. Prayitno and N. W. Suamiati, Global Journal of Pure and Applied Mathematics 13, 2735–2747 (2017).
2. E. Curri, Master’s thesis, University of Agder, Norwegian, 2012.
3. Y. Baykul, lkogretimde matematik ogretimi (Pegam Akademi, Ankara, 2009), pp. 6–8.
4. T. Rattanatumma and V. Puncreobutr, Journal of Education and Practice 7, 194–199 (2016).
5. Depertment of Curriculum Instruction Development, Mathematics by STAD Manual (Kurusapa Printing Ladphroa, Bangkok, 2001).