Railroad Archives Online
- ArquivoD0046 - Andrew Klamka Collection
- Série003 - Great Northern Railway Company (U.S.)
- Subsérie004 - Library
- 002 - Periodicals
- 15 mais...
- ItemGNSemaphoreVol2No4 - 'Great Northern Semaphore' April 1925
- ItemGNSemaphoreVol2No5 - 'Great Northern Semaphore' May 1925
- ItemGNSemaphoreVol2No6 - 'Great Northern Semaphore' June 1925
- ItemGNSemaphoreVol2No7 - 'Great Northern Semaphore' July 1925
- ItemGNSemaphoreVol2No8 - 'Great Northern Semaphore' August 1925
- ItemGNSemaphoreVol2No9 - 'Great Northern Semaphore' September 1925
- ItemGNSemaphoreVol2No10 - 'Great Northern Semaphore' October 1925
- ItemGNSemaphoreVol2No11 - 'Great Northern Semaphore' November 1925
- ItemGNSemaphoreVol2No12 - 'Great Northern Semaphore' December 1925
- 36 mais...