Yudianto, E., Dewi, N. S., & Setiawan, T. B. (2021). Thinking of deduction level students in proving theorem of triangle and its convers based on the steps of Polya. Math Didactic: Jurnal Pendidikan Matematika, 7(1), 61-74. https://doi.org/10.33654/math.v7i1.1199