Servant Leaders: Umar Bin Khattab (13-23 H / 634-644 M). Buletin Al-Turas, [S. l.], v. 22, n. 1, p. 127–144, 2016. DOI: 10.15408/bat.v22i1.2928. Disponível em: https://journal.uinjkt.ac.id/al-turats/article/view/2928. Acesso em: 4 mar. 2026.