เปรมปรี ฐิติรดา. “The Potential for Ecotourism in National Parks, Chaiyaphum”. RMUTI Journal Humanities and Social Sciences 2, no. 1 (June 30, 2015): 118–130. accessed September 4, 2026. https://so05.tci-thaijo.org/index.php/RMUTI_SS/article/view/196005.