Rikharom, R. “Guideline for Service Quality Development of NRRU-Ethics in Nakhon Ratchasima Rajabhat University”. Journal of Humanities and Social Sciences Suratthani Rajabhat University, vol. 11, no. 2, Aug. 2019, pp. 165-88, https://so03.tci-thaijo.org/index.php/jhsc/article/view/199841.