Nyaing. “Efforts to Improve the Ability to Understand the Extent of Trapezium and Kites in Mathematics for Class V Students at SD Negeri I Dadahup Academic Year 2017/2018”. Jurnal Pendidikan, vol. 21, no. 2, Jan. 2021, pp. 127-38, doi:10.52850/jpn.v21i2.2026.