Sasithornwetchakul, A., and T. Choibamroong. “Evaluation of Tourism Management in Nakhon Si Thammarat Province, Thailand as a Secondary Tourism City”. Asian Administration and Management Review, vol. 2, no. 2, July 2019, pp. 23-36, https://so01.tci-thaijo.org/index.php/AAMR/article/view/242826.