Syah, Syafrial, Faulia Anggeraini, and Dang Panagaman Tamba. “The Influence of Employee Productivity and Operational Costs on Increasing Revenue PT. Diamond National Iron Industry Medan”. International Journal of Economics (IJEC) 3, no. 2 (August 15, 2024): 883–897. Accessed November 26, 2024. https://ejournal.ipinternasional.com/index.php/ijec/article/view/1040.