Ahmed kamil abttan al-zubaidi, Rese. “The Efforts of the Caliphs of the First Abbasid Era in Developing the Scientific movement(132 - 232 AH 749 - 848 AD)”. Wasit Journal for Human Sciences, vol. 20, no. 3, July 2024, pp. 472-57, https://doi.org/10.31185/wjfh.Vol20.Iss3.636.