Abdul Hamid, H., and F. @ A. F. Abdul Hamid. “Development of Zakat Administration During Caliph Umar Al-Khattab”. Al-Muqaddimah: Online Journal of Islamic History and Civilization, vol. 6, no. 2, Dec. 2018, pp. 1-14, https://ejournal.um.edu.my/index.php/MUQADDIMAH/article/view/15547.