منصور أحمد إبراهيم. 2008. “Mansour, Ahmad Ibrahim. ‘A Study in the Methodology of Economic Efficiency: ʿUmrān and Khaldūnian Reason As a Model,’ Year 13, Issue 51 (Winter 1429 AH 2008 CE), Pp. 263 -284”. Al-Fikr Al-islāmī Al-muʿāṣir (previously Islamiyat Al-Ma’rifah) 13 (51):263-84. https://doi.org/10.35632/citj.v13i51.1223.