https://pressbooks.pub/travelservicemain/chapter/%e3%80%90whatsapp-support%e3%80%91is-klm-whatsapp-24-7/

https://pressbooks.pub/travelservicemain/chapter/does-air-france-have-free-cancellation/

https://pressbooks.pub/travelservicemain/chapter/%e3%80%90best-time-to-buy%e3%80%91what-day-is-best-to-%ef%bd%82%ef%bd%8f%ef%bd%8f%ef%bd%8b-a-united-flight/

https://pressbooks.pub/travelservicemain/chapter/%e3%80%90early-access%e3%80%91is-air-france-open-on-24-7/

https://www.steadyhealth.com/topics/ways-to-contact-united-airlines-customer-service-by-phone-step-by-step-guide-10

https://pressbooks.pub/travelservicemain/chapter/%e3%80%90open_helpdesk%e3%80%91is-air-france-open-on-24-7/

https://pressbooks.pub/travelservicemain/chapter/does-american-airlines-allow-name-changes-2/

https://pressbooks.pub/travelservicemain/chapter/%e3%80%90best-time-to-buy%e3%80%91which-month-is-qatar-airways-cheapest/

https://pressbooks.pub/travelservicemain/chapter/how-1-855-550-0971-do-i-change-the-name-on-my-delta-ticket/

https://support.google.com/googleplay/android-developer/thread/324714682?hl=en&sjid=12610870310523474551-NA