Rosida, Y., S. M. Sabang, and M. R. Jura. “The Differences in Chemistry Learning Outcomes Using Cooperative Learning Model Type Numbered Head Together With Think Pair Share on the Material of Atomic Structure and Periodic Table in Class XI SMAN 9”. Jurnal Akademika Kimia, vol. 8, no. 3, Aug. 2019, pp. 173-9, doi:10.22487/j24775185.2019.v8.i3.pp173-179.