Sudsaward, S., and D. . Sapphayalak. “Opinion Survey of Industrial Workers about the Need to Develop Essential Skills through Online Lifelong Learning”. ECT Education and Communication Technology Journal, vol. 16, no. 21, Sept. 2021, pp. 48-64, https://so01.tci-thaijo.org/index.php/ectstou/article/view/249569.