https://forum.applefix.vn/threads/detailed-full-list-of-united-airlines%C2%AE-how-to-contact-u-s-support-a-step-by-step-handbook-for-resolving-issues.5147/
https://forum.applefix.vn/threads/full-list-of-united-airlines%C2%AE-u-s-contact-numbers-a-comprehensive-step-by-step-guide-to-reach-the-right-department.5145/
https://community.intel.com/cipcp26785/attachments/cipcp26785/fortran-compiler/176883/2/Live-Support-Speak-to-a-Live-Agent-at-United-Airlines-Available-24-7-.pdf
https://community.intel.com/cipcp26785/attachments/cipcp26785/fortran-compiler/176883/1/Live-Support-Speak-to-a-Live-Agent-at-Southwest-Airlines-Available-24-7-.pdf
https://community.intel.com/cipcp26785/attachments/cipcp26785/fortran-compiler/176881/4/Live-Support-Speak-to-a-Live-Agent-at-Frontier-Airlines-Available-24-7-.pdf