Pechsiri, C., and R. Sukharomana. “Extraction of Problem Events from Web Documents to Construct Cause-Effect Loop”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 10, no. 2-8, July 2018, pp. 37-41, https://jtec.utem.edu.my/jtec/article/view/4455.