Sibarani, J. C., A. P. . Siagian, R. J. . Lubis, and Hasyim. “The Influence of Exports and Investment on GRDP in North Sumatra, 2001 – 2020”. Indonesian Journal of Advanced Research, vol. 2, no. 6, June 2023, pp. 687-96, doi:10.55927/ijar.v2i6.4543.