"The use of multiple stages of service queuing models In the analysis of passenger service in Sulaymaniyah International Airport" (2014) Al Kut Journal of Economics and Administrative Sciences, 6(16), ص 111–128. موجود في: https://kjeas.uowasit.edu.iq/index.php/kjeas/article/view/204 (تاريخ الوصول: 1 سبتمبر 2026).