Delta Air Lines System Timetable 1981 June 1
MLA
Delta Air Lines, Inc.. "Delta Air Lines System Timetable 1981 June 1." Delta Flight Museum. 1981-06-01, https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19810601.
APA
Delta Air Lines, Inc. (1981-06-01). Delta Air Lines System Timetable 1981 June 1. Retrieved from https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19810601
Chicago
Delta Air Lines, Inc.. "Delta Air Lines System Timetable 1981 June 1." 1981-06-01. May 10, 2026. https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19810601.
