Al–yasari, H. khudhair murad and Al-Zahawi, A.A.S.A.Q. (2021) “The conflict between the Papacy and the German Empire during the seventh century AH / thirteenth century AD and its impact on the Crusader movement”, Al-Adab Journal, 2(139), pp. 173–200. doi:10.31973/aj.v2i139.2620.