https://www.des.unipi.gr/applications/sites/default/files/webform/americanstudies/Talk-To-Someone-At-American-Airlines-Usa-Through-Contact-Numbers-A-Step-by-Step-Guide.pdf https://www.des.unipi.gr/applications/sites/default/files/webform/americanstudies/Talk-To-Someone-At-United-Airlines-Usa-Through-Contact-Numbers-A-Step-by-Step-Guide.pdf https://www.des.unipi.gr/applications/sites/default/files/webform/americanstudies/Talk-To-Someone-At-Delta-Airlines-Usa-Through-Contact-Numbers-A-Step-by-Step-Guide.pdf