D. Haryani, A. Subagjo, M. Hamdani, Q. . Ali Hasan, dan N. Widyanti, “ANALYSIS OF THE DIFFICULTIES OF CLASS X STUDENTS OF SMKN 4 PALANGKA RAYA IN SOLVING TRIGONOMETRY PROBLEMS”, JPN, vol. 23, no. 1, hlm. 29–38, Jun 2022.