Delta Air Lines System Timetable 1981 April 26
MLA
Delta Air Lines, Inc.. "Delta Air Lines System Timetable 1981 April 26." Delta Flight Museum. 1981-04-26, https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19810426.
APA
Delta Air Lines, Inc. (1981-04-26). Delta Air Lines System Timetable 1981 April 26. Retrieved from https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19810426
Chicago
Delta Air Lines, Inc.. "Delta Air Lines System Timetable 1981 April 26." 1981-04-26. May 11, 2026. https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19810426.
