Omar, Z., and S. Salih. “Relationship Marketing and Its Role in Marketing Excellence: An Exploratory Study of the Opinions of a Sample of Managers in Four- and Five-Star Hotels in the City of Duhok”. Humanities Journal of University of Zakho, vol. 10, no. 4, Dec. 2022, pp. 1052-68, doi:10.26436/hjuoz.2022.10.4.865.