Sharif, D. A. .; Abdullah , S. A.; Othman, B. A. .; Abdullah, Y. H. . The Impact of Employee’s Income Grades on Tourism Demand: : An Exploratory Study About Employees Opinion to Their Demand of Tourism in Koya Technical Institute /Iraq. Polytechnic J. Hum. Soc. Sci. 2024, 5, 555-566.