Buhungo, Trisnawaty Junus, et al. “Learning Tools Quality of Problem-Based Learning Model in Contextual Teaching and Learning Approach on Elasticity and Hooke’s Law Materials”. Jurnal Penelitian Pendidikan IPA, vol. 9, no. 3, Mar. 2023, pp. 1092-8, doi:10.29303/jppipa.v9i3.3127.