Obaid Issa, A., & 		Ali Saud Al-Jubouri, A.
2019 Mar 31.  Diwan Al-Kharaj and Al-Ataa Al-Nashra and Development until the end of the Umayyad era. Journal of Tikrit university for humanities - مجلة جامعة تكريت للعلوم الانسانية. [Online] 23:4