BR SIBURIAN, Berli Anni; LUBIS, Rifka Hadia; SIPAHUTAR, Hadijah. The Effect of Operational Costs on Sales at Mujur Jaya Photocopy Business in Pandan, Central Tapanuli Regency. Journal of Economics, Management and Accounting (JEMA) , [S. l.], v. 3, n. 01, p. 87–91, 2026. Disponível em: https://jurnal.devitara.or.id/index.php/ekonomi/article/view/345. Acesso em: 17 mar. 2026.