| https://ctl.gatech.edu/sites/default/files/webform/teaching_with_technology_partner/_sid_/delta-te-l-f-ono-52-c-mo-llamar-a-delta-airlines-en-m-xico.pdf |
| https://ctl.gatech.edu/sites/default/files/webform/teaching_with_technology_partner/_sid_/como-puedo-comunicarme-con-delta.pdf |
| https://ctl.gatech.edu/sites/default/files/webform/teaching_with_technology_partner/_sid_/como-hablar-con-alguien-en-delta.pdf |
| https://ctl.gatech.edu/sites/default/files/webform/teaching_with_technology_partner/9651/como-puedo-llamar-a-british-airways-desde-mexico.pdf |
