W. Warsono, E. Russels, W. Wamiliana, W. Widiarti, and M. Usman, “Vector Autoregressive with Exogenous Variable Model and its Application in Modeling and Forecasting Energy Data: Case Study of PTBA and HRUM Energy”, IJEEP, vol. 9, no. 2, pp. 390–398, Feb. 2019.