https://regions-and-cities.europa.eu/sites/default/files/webform/multimedia_center/_sid_/Conectando-con-Copa-Airlines-desde-M%C3%A9xico–Todas-tus-Opciones-de-Contacto-FAQ%5E.pdf
https://polyamory.com/threads/official-fastest-ways-to-speak-to-a-human-at-united-airlines-r-direct-access-tips.158242/
https://regions-and-cities.europa.eu/sites/default/files/webform/multimedia_center/_sid_/GUIARAPIDAComocambiarelpasajedeFrontier_2.pdf
http://rcindia.org/rc-india-forum/33-ways-to-reach-how-do-i-talk-to-someone-at-expedia-a-comprehensive-guide/new/#new