Tanjung, Y. I. T., F. Festiyed, S. D. Diliarosta, J. Jubaidah, and A. P. S. Sanjaya. “Analysis of Students’ Problem Solving Skills Based on Heller Indicator”. Pegem Journal of Education and Instruction, vol. 14, no. 4, July 2024, pp. 421-33, doi:10.47750/pegegog.14.04.40.