https://collaboratory.gse.upenn.edu/sites/default/files/webform/how-much-does-aeromexico-charge-to-change-a-flight.pdf

https://sites.google.com/view/lamar-a-delta-airlines-/home

https://collaboratory.gse.upenn.edu/sites/default/files/webform/hablarahora%C2%BFcomo-hablo-con-un-agente-de-expedia.pdf

LUI;

https://intercom.help/agregar-infante/en/articles/11719452-25-como-contactar-a-un-humano-en-alaska-por-telefono-chat-o-correo-electronico-guia-de-ayuda-completa

https://nch.invisionzone.com/topic/87603-12-ways-to-talk-to-someone-at-delta-via-phone-email-or-chat-options-a-step-by-step-guide/

https://collaboratory.gse.upenn.edu/sites/default/files/webform/05-ways-to-access-how-can-i-speak-to-someone-at-quickbookstm-a-step-by-step-best-guide.pdf

https://nch.invisionzone.com/topic/87594-12-ways-to-talk-to-someone-at-united-via-phone-email-or-chat-options-a-step-by-step-guide/

https://pantip.com/topic/43606678

https://collaboratory.gse.upenn.edu/sites/default/files/webform/how-do-i-contact-southwest-customer-service-24-7.pdf