Sasria, Nia. “Composite Manufacturing of Coir Fiber-Reinforced Polyester As a Motorcycle Helmet Material”. JMPM (Jurnal Material dan Proses Manufaktur) 6, no. 1 (September 10, 2022): 48–56. Accessed April 29, 2025. https://journal.umy.ac.id/index.php/jmpm/article/view/13756.