https://collaboratory.gse.upenn.edu/sites/default/files/webform/is-southwest-customer-service-24-hours.pdf

https://pressbooks.pub/namecorrection/chapter/10-ways-to-contact-a-human-at-frontier-airlines-via-phone-chat-or-email-support/

https://pressbooks.pub/namecorrection/chapter/20-ways-to-reach-a-live-agent-at-frontier-airlines-customer-service-easy-help-guide/

https://www.supramania.com/threads/complete-guide-how-do-i-know-if-my-lufthansa-flight-is-refundable.335668/

https://www.supramania.com/threads/how-do-i-know-if-my-lufthansa-flight-is-refundable-contact-us.335657/

https://pressbooks.pub/namecorrection/chapter/como-cambio-de-nombre-en-billete-de-avion-american/

https://pressbooks.pub/namecorrection/chapter/como-edicion-de-nombre-en-el-billete-american/

https://www.supramania.com/threads/how-do-i-know-if-my-lufthansa-flight-is-refundable.335649/

https://pressbooks.pub/namecorrection/part/speak-to-live-agent-at-frontier-airlines/

https://nch.invisionzone.com/topic/87627-12-ways-to-phone-to-someone-at-delta-via-phone-email-or-chat-options-a-step-by-step-guide/