Nurhidayah N, Waskitoningtyas RS. Implementation of problem-based learning models to improve understanding of mathematics concepts at Al-Hassan high school. J. Math Educ. Nusant. Wahana Publ. Karya Tulis Ilm. di Bid. Pendidik. Mat. [Internet]. 2023 May 31 [cited 2025 Jan. 9];9(1):76-88. Available from: https://ojs.unpkediri.ac.id/index.php/matematika/article/view/19544