Tadngoen, Rungnapa, Charin Mangkhang, and Sawaeng Saenbutr. 2021. “Guidelines for Integrative Environmental Learning to Enhance Environmental Citizenship Skills of Secondary Stu-Dents at Udomdarunee School”. Trends of Humanities and Social Sciences Research 9 (2):53-71. https://so03.tci-thaijo.org/index.php/Humanties-up/article/view/222373.