Thinkamchoet, J., and Wongchantra, P. “The development of camp on natural resources and environmental sonservation in the ASEAN for youths in Roi-et province”. International Journal of Agricultural Technology, vol. 14, no. 7, Dec. 2018, pp. 2077-96, https://li04.tci-thaijo.org/index.php/IJAT/article/view/10307.