WASET
    M. Rodionov and  Z. Dedovets,  Academic Motivation Maintenance for Students While Solving Mathematical Problems in the Middle School.   journal   = {International Journal of Educational and Pedagogical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    September 2015, vol. 106(10). 3420 - 3423
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/10002557.