Railroad Archives Online
- FondoE0480 - Great Northern Railway Historical Society Miscellaneous Collection
- Serie003 - Great Northern Railway Company (U.S.)
- Sottoserie008 - Ephemera
- Unità documentariaEMPIRE BUILDER RADIO STORY CONTEST - Empire Builder Radio Story Contest Pamphlet, 1929
- Unità documentariaTHE EMPIRE BUILDER RADIO - Advertising Pamphlet for "The Empire Builders", 1929
- Unità documentariaWESTWARD TIDE - Radio Show Script for "The Westward Tide", 1929