Purba, Leony Sanga Lamsari, et al. “The Differences of Achievement of the National Olympiad in Chemistry at the Public and Private Senior High School by Utilizing Quizizz Media”. Jurnal Pendidikan Kimia, vol. 13, no. 1, Apr. 2021, pp. 69-77, doi:10.24114/jpkim.v13i1.24146.