https://forums.serebii.net/threads/ways-to-reach-frontier-airlines-customer-service-usa-by-phone-step-by-step-guide.782576/

https://support.google.com/calendar/thread/338100632?hl=en&sjid=13596494584594865807-NA

https://forums.serebii.net/threads/ways-to-reach-frontier-customer-service-by-us-phone-chat-air-travel.782575/

https://travel.stackexchange.com/questions/194852/ex-faqswhat-days-are-flights-cheapest-on-expedia

https://www.italki.com/en/post/IartPMWABI9s62PWGt0tFL

https://support.google.com/edu/classroom/thread/338101171?hl=en&sjid=7025340637366444665-NA

https://forums.serebii.net/threads/ultimate-frontier-support-guide-how-to-reach-any-carrier-via-phone-chat-and-email.782573/

https://www.sgreefclub.com/forum/topic/250395-faqs~help-can-i-talk-to-a-real-person-at-quicken/

https://support.google.com/edu/classroom/thread/338100902?hl=en&sjid=7025340637366444665-NA

https://forums.serebii.net/threads/ways-to-call-lufthansa-airlines-customer-service-phone-chat-and-email-options-explained-guide.782572/