Natakam, Sunanta, and Sunantha Laowansiri. “WATER QUALITY ANALYSIS FOR RECREATIONAL WATERFALLS OF PHU RUEA NATIONAL PARK, LOEI PROVINCE”. Life Sciences and Environment Journal 19, no. 2 (September 23, 2018): 358-368. Accessed December 9, 2021. https://ph01.tci-thaijo.org/index.php/psru/article/view/111606.