Mohd Nor, Radieah. 2013. “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 8 (2):81-88. https://ijie.um.edu.my/index.php/JAT/article/view/8663.