Railroad Archives Online
- CollectionD0491 - Warner Swarner Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3002 - Depots and Freighthouses
- ItemWBSGNDepot096 - Northern Pacific Depot at Helena, Montana, 2014