*Northwest Airlines Schedule 1938 December 1
MLA
Northwest Airlines. "*Northwest Airlines Schedule 1938 December 1." Delta Flight Museum. 1938-12-01, https://dlg.galileo.usg.edu/do:delta_nwa-tt_nwa-tt-19381201.
APA
Northwest Airlines (1938-12-01). *Northwest Airlines Schedule 1938 December 1. Retrieved from https://dlg.galileo.usg.edu/do:delta_nwa-tt_nwa-tt-19381201
Chicago
Northwest Airlines. "*Northwest Airlines Schedule 1938 December 1." 1938-12-01. June 20, 2025. https://dlg.galileo.usg.edu/do:delta_nwa-tt_nwa-tt-19381201.
