Br Siburian, Berli Anni, Rifka Hadia Lubis, and Hadijah Sipahutar. 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.