Kawkumpa, S., T. Saisema, O. Seoob, C. Trakankit, P. Atorngitjawat, and W. Sakulsaknimitr. “Synthesis of Polyurethane from Glycolysis Product of PET Using ZnO As Catalyst”. RMUTSB ACADEMIC JOURNAL, vol. 7, no. 1, June 2019, pp. 29-39, https://li01.tci-thaijo.org/index.php/rmutsb-sci/article/view/150479.