Railroad Archives Online
- FondiD0036 - George Werkema Collection
- Serija001 - Burlington Northern Railroad Company
- Podserija014 - Photographs
- 001 - Railroads--Equipment and Supplies
- 004 - Railroad Passenger Cars
- DokumentWerkema378 - Burlington Northern railway post office car 1931 in 1973.
- Dokumentimg322 - Burlington Northern Passenger Car at Denver, Colorado, 1981
- Dokumentimg323 - Burlington Northern Passenger Car at Denver, Colorado, 1981
- Dokumentimg324 - Burlington Northern Passenger Car at Denver, Colorado, 1985