Hemachandra เข็มชัย, and Euapitaksakul นาตยา. “Heat Sealing of Polypopylene Film in Flexible Packaging”. Journal of Metals, Materials and Minerals 7, no. 2 (August 21, 2022): 53–66. Accessed May 4, 2025. https://www.jmmm.material.chula.ac.th/index.php/jmmm/article/view/1459.