Wirdha, W., Hatibe, A. ., & Darsikin, D. (2017). The Effect of Logic Concept Cognitive Development on Physics Science Learning Achievement with Problem Solving Approach of the Eighth Grade Students of SMP Negeri 16 Palu. Jurnal Universitas Tadulako, 1(1), 1-8. https://doi.org/10.22487/j25490192.2017.v1.i1.pp1-8