Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series001 - Burlington Northern Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3004 - Railroad Passenger Cars
- ItemWerkema378 - Burlington Northern railway post office car 1931 in 1973.
- Itemimg322 - Burlington Northern Passenger Car at Denver, Colorado, 1981
- Itemimg323 - Burlington Northern Passenger Car at Denver, Colorado, 1981
- Itemimg324 - Burlington Northern Passenger Car at Denver, Colorado, 1985