Tanayut Chaitongrat, Surapong Liwthaisong, Preenithi Aksorn, Wuttipong Kusonkhum, and Narong Leungbootnak. “CAUSAL RELATIONSHIP MODEL OF PROBLEMS IN PUBLIC SECTOR PROCUREMENT”. GEOMATE Journal, vol. 20, no. 80, Apr. 2021, pp. 52-58, https://geomatejournal.com/geomate/article/view/298.