Railroad Archives Online
- FondsD0046 - Andrew Klamka Collection
- Série003 - Great Northern Railway Company (U.S.)
- Sous-série004 - Library
- 002 - Periodicals
- 21 en plus...
- PièceGNSemaphoreVol2No10 - 'Great Northern Semaphore' October 1925
- PièceGNSemaphoreVol2No11 - 'Great Northern Semaphore' November 1925
- PièceGNSemaphoreVol2No12 - 'Great Northern Semaphore' December 1925
- PièceGNSemaphoreVol3No1 - 'Great Northern Semaphore' January 1926
- PièceGNSemaphoreVol3No2 - 'Great Northern Semaphore' February 1926
- PièceGNSemaphoreVol3No3 - 'Great Northern Semaphore' March 1926
- PièceGNSemaphoreVol3No4 - 'Great Northern Semaphore' April 1926
- PièceGNSemaphoreVol3No5 - 'Great Northern Semaphore' May 1926
- PièceGNSemaphoreVol3No6 - 'Great Northern Semaphore' June 1926
- 30 en plus...