Dwi Novita, R., Tien Aminatun, and Rihab Wit Daryono. “E-Modules Through Flipped Classroom and PBL Models on Environmental Pollution Material to Increase Problem-Solving Ability”. Journal of Education Technology, vol. 6, no. 4, Dec. 2022, pp. 744-5, doi:10.23887/jet.v6i4.51656.