Kawiak, Ewelina. “Heuristic Method of G. Polya in the Opinion of the Early-School Education Teachers”. Journal of Vasyl Stefanyk Precarpathian National University 11, no. 1 (March 31, 2024): 103–110. Accessed November 21, 2024. https://ktipe.pnu.edu.ua/index.php/jpnu/article/view/7841.