Sakulkaew, Kartpan, and Prasert Saeju. “Study of factors effecting indentation hardness index of natural latex foam”. Bulletin of Applied Sciences 8, no. 8 (October 7, 2022): 17–24. accessed December 11, 2025. https://ph03.tci-thaijo.org/index.php/BAS/article/view/249.