Heru, Heru, et al. “Desain Modul Matematika Siswa Berbasis PMRI Kelas IV Sekolah Dasar”. Jurnal Pendidikan Matematika RAFA, vol. 6, no. 2, Dec. 2020, pp. 170-84, https://doi.org/10.19109/jpmrafa.v6i2.11302.