Rangkuti, S. M. B., Raina Linda Sari, and Irsyad. “The Influence of Investment Indirect and Direct Expenditure Work Force and Education on Economic Growth in North Sumatera”. Enrichment : Journal of Management, Vol. 13, no. 2, June 2023, pp. 774-83, doi:10.35335/enrichment.v13i2.1318.