Arif Fradina, R., Cahyono, E., & Sumarni, W. (2022). Development of Natural and Social Science Learning Programme (IPAS) in Elementary School with Understanding by Design (UbD) Framework to Improve Concept Mastery and Problem-Solving Ability. Journal of Primary Education, 11(3), 399-407. https://doi.org/10.15294/jpe.v11i3.77327