Rezky, Raizal, and Ernawati Jais. “Hyphotetical Learning Trajectory: Pemecahan Masalah Materi Sistem Persamaan Linear Dua Variabel”. Mandalika Mathematics and Educations Journal, vol. 2, no. 2, July 2020, pp. 92-101, doi:10.29303/jm.v2i2.1780.