Apri Putriana, et al. “ANALISIS KESULITAN BELAJAR SISWA POKOK BAHASAN BANGUN DATAR DI ERA COVID-19 SISWAKELAS VI SDNEGERI 050656 STABAT”. Jurnal Serunai Matematika, vol. 13, no. 2, Nov. 2021, pp. 99-106, https://www.ejournal.stkipbudidaya.ac.id/index.php/matematika/article/view/435.