Ruttikal Siphala และ Natchanok Jansawang. (2023) The Development of Learning Achievement, Problem-Solving Ability, and Analytical Thinking of Grade 9 Students on Ecosystems and Biological Diversity through Problem-Based Learning. <i>Interdisciplinary Academic and Research Journal</i>, <i>3</i>(5), 549-568.Ruttikal Siphala และ Natchanok Jansawang. "The Development of Learning Achievement, Problem-Solving Ability, and Analytical Thinking of Grade 9 Students on Ecosystems and Biological Diversity through Problem-Based Learning". Interdisciplinary Academic and Research Journal 3 (2023):549-568.Ruttikal Siphala และ Natchanok Jansawang. The Development of Learning Achievement, Problem-Solving Ability, and Analytical Thinking of Grade 9 Students on Ecosystems and Biological Diversity through Problem-Based Learning. DR.KEN Institute of Academic Development and Promotion.:ม.ป.ท. 2023.