Yusuf, M., and S. Tirtayasa. “Employee Competence, Leadership Style and Employee Performance: Mediating Role of Work Motivation at PT Perkebunan Nusantara IV Regional VI”. TAMBUN – Theory and Application in Management, Business, and the Unity of Nations, vol. 2, no. 01, Apr. 2026, pp. 13-22, https://ejournal.cria.or.id/index.php/TAMBUN/article/view/446.