Br Siburian, B. A., Lubis, R. H., & Sipahutar, H. (2026). The Effect of Operational Costs on Sales at Mujur Jaya Photocopy Business in Pandan, Central Tapanuli Regency. Journal of Economics, Management and Accounting (JEMA) , 3(01), 87-91. https://jurnal.devitara.or.id/index.php/ekonomi/article/view/345