https://collaboratory.gse.upenn.edu/sites/default/files/webform/contact-methods-united-airlines-customer-service-number-an-all-inclusive-guide_0.pdf

https://collaboratory.gse.upenn.edu/sites/default/files/webform/expedia-customer-usa-phone-numbers-a-simple-step-guide.pdf

https://forum.ersatzteilshop.de/t/complete-list-of-official-expedia-customer-service-in-the-usa-the-step-by-step-detailed-guide/2521

https://community.geph.io/t/topic/19126

https://forum.ersatzteilshop.de/t/full-list-of-official-qatar-airways-service-24-7-live-person-support-numbers-a-complete-guide/2506

https://forum.ersatzteilshop.de/t/full-list-of-expedia-customer-service-24-7-live-person-support-numbers-a-complete-guide/2511

https://collaboratory.gse.upenn.edu/sites/default/files/webform/contact-methods-frontier-airlines-customer-service-number-an-all-inclusive-guide_0.pdfhttps://collaboratory.gse.upenn.edu/sites/default/files/webform/contact-methods-frontier-airlines-customer-service-number-an-all-inclusive-guide_0.pdf

https://collaboratory.gse.upenn.edu/sites/default/files/webform/contact-methods-alaska-airlines-customer-service-number-an-all-inclusive-guide_0.pdf

https://community.geph.io/t/topic/19063

https://collaboratory.gse.upenn.edu/sites/default/files/webform/completes-list-of-official-expedia-usa-contact-numbers-the-full-detailed-guide-2025-26.pdf