https://pressbooks.pub/namecorrection/chapter/7-ways-to-talk-to-a-live-person-at-frontier-airlines-step-by-step-contact-guide/

https://epicflightacademy.com/aviation-forums/topic/67-ways-to-call-swiss-international-airlines-usa-contact-full-detailed-guide/#new-topic-0

https://epicflightacademy.com/aviation-forums/topic/46-ways-to-call-swiss-international-airlines-usa-contact-full-detailed-guide/#new-topic-0

https://pressbooks.pub/namecorrection/chapter/how-to-talk-to-someone-at-frontier-airlines-8-ways-to-contact-via-phone-email-chat/

https://collaboratory.gse.upenn.edu/sites/default/files/webform/how-do-i-contact-lufthansa-baggage.pdf

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/