Delta Air Lines System Timetable 1940 May 15
MLA
Delta Air Corporation. "Delta Air Lines System Timetable 1940 May 15." Delta Flight Museum. 1940-05-15, https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19400515.
APA
Delta Air Corporation (1940-05-15). Delta Air Lines System Timetable 1940 May 15. Retrieved from https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19400515
Chicago
Delta Air Corporation. "Delta Air Lines System Timetable 1940 May 15." 1940-05-15. May 9, 2026. https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19400515.
