https://ia902805.us.archive.org/29/items/delta-official-numbers/Official_Final_List_of_Delta_CUSTOMER_Service_Contact_Number_24_7.pdf
https://ia600502.us.archive.org/32/items/delta-number-official/FAQs_Official_List_of_Delta_CUSTOMER_Service_Contact_Number.pdf
https://ia600606.us.archive.org/11/items/delta-air-official/Final_Official_List_of_Delta_CUSTOMER_Service_Number_24_7.pdf
https://ia600406.us.archive.org/19/items/delta-official-services/FAQs_Final_Official_List_of_Delta_CUSTOMER_Service_24_7.pdf
https://ia902901.us.archive.org/8/items/official-airlines-services/Official_Finall_List_of_Delta_CUSTOMER_Service_Contact_Number.pdf