https://www.transfermarkt.com/-cancel-guide-how-long-do-you-have-to-cancel-with-frontier-100-cancel__back/thread/forum/696/thread_id/52650/page/1#anchor_49508
https://community.snowsoftware.com/s/question/0D5Td00000GFRgmKAH/24horasespa%C3%B1ol-c%C3%B3mo-llamar-a-american-airlines-en-espa%C3%B1ol-telefono-american
https://www.transfermarkt.com/-solution-with-refund-does-frontier-refund-you-if-you-cancel-travel-guide/thread/forum/696/thread_id/52648/page/1#anchor_49506
https://www.transfermarkt.com/-get-refund-1-86-6-73-8-07-38-does-frontier-refund-you-if-you-cancel-/thread/forum/696/thread_id/52646/page/1#anchor_49504
https://community.lumivero.com/s/question/0D5Jw00000dL4geKAC/f9%CE%B1%C3%AFr%EF%BE%9A%C3%AF%CE%B7%CE%B5%C5%A1-does-frontier-give-you-24-hrs-to-cancel