Badkook, Basem. “Study to Determine the Aircraft on Ground (AOG) Cost of the Boeing 777 Fleet at X Airline”. American Scientific Research Journal for Engineering, Technology, and Sciences 25, no. 1 (September 20, 2016): 51–71. Accessed September 17, 2025. https://www.asrjetsjournal.org/American_Scientific_Journal/article/view/2110.