Suhartono, Suhartono, Dedy Dwi Prastyo, Heri Kuswanto, and Muhammad Hisyam Lee. “Comparison Between VAR, GSTAR, FFNN-VAR and FFNN-GSTAR Models for Forecasting Oil Production”. MATEMATIKA: Malaysian Journal of Industrial and Applied Mathematics 34, no. 1 (May 28, 2018): 103–111. Accessed September 19, 2021. https://matematika.utm.my/index.php/matematika/article/view/1040.