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]. 2023May31 [cited 2024Nov.24];9(1):76-8. Available from: https://ojs.unpkediri.ac.id/index.php/matematika/article/view/19544