Ahmed kamil abttan al-zubaidi, R. The Efforts of the Caliphs of the First Abbasid Era in Developing the Scientific Movement(132 - 232 AH 749 - 848 AD). wjfh 2024, 20 (3), 472-457. https://doi.org/10.31185/wjfh.Vol20.Iss3.636.