Jong, Oi-Ka, et al. “Factorial Analysis of Tensile Properties of Areca Leaf Sheath (ALS) Subjected to Flattening”. International Journal of Integrated Engineering, vol. 13, no. 2, Dec. 2020, pp. 82-89, https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/6495.