Bussaya Rattanasupa, and Wirunya Keawwattana. “The Development of Rubber Compound based on Natural Rubber (NR) and Ethylene-Propylene-Diene-Monomer (EPDM) Rubber for Playground Rubber Mat”. Agriculture and Natural Resources, vol. 41, no. 5, Dec. 2007, pp. 239-47, https://li01.tci-thaijo.org/index.php/anres/article/view/244374.