ตู้พิจิตร ช., พงศ์ขจร ว., and จิระวิชิตชัย น. “IT Service Operation Improvement With ITIL (Case Study of Data Products Toppan Forms Ltd)”. Progress in Applied Science and Technology, vol. 7, no. 1, June 2017, pp. 134-43, https://ph02.tci-thaijo.org/index.php/past/article/view/243124.