Mohd Nor, R. “PENGURUSAN BAITUMAL ERA PEMERINTAHAN KHALIFAH UMAR BIN ABDUL AZIZ (Management of Treasury During Era the Reign of Caliph Umar Bin Abdul Aziz)”. Journal of Al-Tamaddun, vol. 8, no. 2, Dec. 2013, pp. 81-88, https://vmis.um.edu.my/index.php/JAT/article/view/8663.