Efni, L. dkk. 2024. Development of Mathematics Learning Devices with GDL Models to Improve Mathematical Problem-Solving Ability of Class VII Junior High School. Jurnal Bintang Pendidikan Indonesia. 2, 4 (Agu 2024), 57–65. DOI:https://doi.org/10.55606/jubpi.v2i4.3247.