Lawong, Amin, and Charnnarong Saikaew. 2017. “Factors and Optimal Operating Condition of Process Factors Affecting the Quality of Polyethylene Terephthalate Bottle”. Asia-Pacific Journal of Science and Technology 19 (3):385-98. https://so01.tci-thaijo.org/index.php/APST/article/view/82964.