Phimphromma, N. . “The Measurement and Mapping of Noise Levels in a Factory Plastic Sack Production Process in Ratchaburi”. Journal of Energy and Environment Technology of Graduate School Siam Technology College, vol. 8, no. 2, Dec. 2021, pp. 36-44, https://ph01.tci-thaijo.org/index.php/JEET/article/view/245428.