Palakorn Niamjapo. (2024) Developing Mathematical Problem-Solving Skills Using Polya's Steps: A Problem-Based Learning Approach in Combinatorics for Grade 11 Students. <i>Journal of Science and Science Education</i>, <i>7</i>(2), 398-406.Palakorn Niamjapo. "Developing Mathematical Problem-Solving Skills Using Polya's Steps: A Problem-Based Learning Approach in Combinatorics for Grade 11 Students". Journal of Science and Science Education 7 (2024):398-406.Palakorn Niamjapo. Developing Mathematical Problem-Solving Skills Using Polya's Steps: A Problem-Based Learning Approach in Combinatorics for Grade 11 Students. Faculty of Science, Ubon Ratchathani University:ม.ป.ท. 2024.