Delta Air Lines System Timetable 1939 May 15
MLA
Delta Air Corporation. "Delta Air Lines System Timetable 1939 May 15." Delta Flight Museum. 1939-05-15, https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19390515.
APA
Delta Air Corporation (1939-05-15). Delta Air Lines System Timetable 1939 May 15. Retrieved from https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19390515
Chicago
Delta Air Corporation. "Delta Air Lines System Timetable 1939 May 15." 1939-05-15. May 10, 2026. https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19390515.
