C. E. Morkle and C. A. Ali, “APOS Framework Didactize Equivalence Linear Simultaneous Equations in Senior High School Mathematics”, J. Res. Math. Sci. Technol. Educ., vol. 1, no. 2, pp. 84–100, Oct. 2024, doi: 10.70232/jrmste.v1i2.13.