Delta Air Lines System Timetable 1981 December 1
MLA
Delta Air Lines, Inc.. "Delta Air Lines System Timetable 1981 December 1." Delta Flight Museum. 1981-12-01, https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19811201.
APA
Delta Air Lines, Inc. (1981-12-01). Delta Air Lines System Timetable 1981 December 1. Retrieved from https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19811201
Chicago
Delta Air Lines, Inc.. "Delta Air Lines System Timetable 1981 December 1." 1981-12-01. July 13, 2025. https://dlg.galileo.usg.edu/do:delta_dal-tt_dal-tt-19811201.
