The Role Of Operational Efficiency In Mediating The Influence Of Der, Roa, And Company Size On Operational Performance. Center of Economic Students Journal, [S. l.], v. 9, n. 3, p. 51–70, 2026. DOI: 10.56750/cesjv9i3.1823. Disponível em: https://jurnal.fe.umi.ac.id/index.php/CSEJ/article/view/1823. Acesso em: 27 jul. 2026.