HAMAD, S.J. 2021. The Scientific Efforts of the Caliph Omer Bin Al-Khatab in Muslim Civilization (Visions and Dreams as an example) (13H-24H/634M-644M). Journal of Tikrit University for Humanities. 28, 3, 2 (Mar. 2021), 402–418. DOI:https://doi.org/10.25130/jtuh.28.3.2.2021.23.