Tirta, G. A. R., P. Prabowo, and S. Kuntjoro. “Development of Physics Teaching Instruments Belong to Cooperative Group Investigation Model to Improve Students Self-Efficacy and Learning Achievement”. JPPS (Jurnal Penelitian Pendidikan Sains), vol. 7, no. 2, June 2018, pp. 1464-71, doi:10.26740/jpps.v7n2.p1464-1471.