Railroad Archives Online
- ArquivoD0046 - Andrew Klamka Collection
- Série003 - Great Northern Railway Company (U.S.)
- Subsérie004 - Library
- 002 - Periodicals
- 30 mais...
- ItemGNSemaphoreVol3No7 - 'Great Northern Semaphore' July 1926
- ItemGNSemaphoreVol3No8 - 'Great Northern Semaphore' August 1926
- ItemGNSemaphoreVol3No9 - 'Great Northern Semaphore' September 1926
- ItemGNSemaphoreVol3No10 - 'Great Northern Semaphore' October 1926
- ItemGNSemaphoreVol3No11 - 'Great Northern Semaphore' November 1926
- ItemGNSemaphoreVol3No12 - 'Great Northern Semaphore' December 1926
- ItemGNSemaphoreVol4No1 - 'Great Northern Semaphore' January 1927
- ItemGNSemaphoreVol4No2 - 'Great Northern Semaphore' February 1927
- ItemGNSemaphoreVol4No3 - 'Great Northern Semaphore' March 1927
- 21 mais...