https://summer.oregonstate.edu/sites/drupal.oregonstate.edu/files/a-full-list-of-delta-airlines-customer-usa-contact-numbers-guide.pdf https://summer.oregonstate.edu/sites/drupal.oregonstate.edu/files/contact-methods-united-airlinesr-usa-contact-care-numbers-an-all-inclusive-guide.pdf https://summer.oregonstate.edu/sites/drupal.oregonstate.edu/files/full-list-of-delta-airlines-customer-contact-numbers-in-the-usa-an-official-guide.pdf https://summer.oregonstate.edu/sites/drupal.oregonstate.edu/files/full-list-of-official-deltatm-airlinestm-customerr-contact-numbers-in-the-usa-full-detailed-guide.pdf https://summer.oregonstate.edu/sites/drupal.oregonstate.edu/files/official-united-airlines-customer-service-number-an-all-inclusive-guide.pdf