“Analysis of Need for Teaching Materials Based STEM-PjBL Assisted by Instructional Videos on Topic Voltaic Cells : Analisis Kebutuhan Bahan Ajar Berbasis STEM-PjBL Berbantuan Video Pembelajaran Pada Topik Sel Volta”, pedagogia, vol. 9, no. 2, Aug. 2020, doi: 10.21070/pedagogia.v9i2.736.