Welni E, Fauzi A, Usmeldi U. The Development of Problem Based Learning Device for Junior High School Natural Science Class for Learning Substance Pressure and its Daily Use Material. IJEDS [Internet]. 2020 Jan. 17 [cited 2026 May 31];2(1):199-208. Available from: http://ijeds.ppj.unp.ac.id/index.php/IJEDS/article/view/246