M. Rodionov and  Z. Dedovets,  Developing Proof Demonstration Skills in Teaching Mathematics in the Secondary School.   journal   = {International Journal of Educational and Pedagogical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    April 2019, vol. 149(5). 588 - 593
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/10010340.