Https://www.des.unipi.gr/applications/sites/default/files/webform/Complete%20L.i.s.t%20of%20OTA%20Southwest%20Airlines%C2%AE%20Customer%20Service%20Number%20in%20the%20US.pdf https://www.des.unipi.gr/applications/sites/default/files/webform/Complete%20L.i.s.t%20of%20OTA%20Southwest%20Airlines%C2%AE%20Customer%20Service%20Number%20in%20the%20US.pdf