Natakam, S., and S. Laowansiri. “WATER QUALITY ANALYSIS FOR RECREATIONAL WATERFALLS OF PHU RUEA NATIONAL PARK, LOEI PROVINCE”. Life Sciences and Environment Journal, vol. 19, no. 2, Sept. 2018, pp. 358-6, https://ph01.tci-thaijo.org/index.php/psru/article/view/111606.