Railroad Archives Online
- ArquivoD0046 - Andrew Klamka Collection
- Série003 - Great Northern Railway Company (U.S.)
- Subsérie004 - Library
- 002 - Periodicals
- 25 mais...
- ItemGNSemaphoreVol3No2 - 'Great Northern Semaphore' February 1926
- ItemGNSemaphoreVol3No3 - 'Great Northern Semaphore' March 1926
- ItemGNSemaphoreVol3No4 - 'Great Northern Semaphore' April 1926
- ItemGNSemaphoreVol3No5 - 'Great Northern Semaphore' May 1926
- ItemGNSemaphoreVol3No6 - 'Great Northern Semaphore' June 1926
- ItemGNSemaphoreVol3No7 - 'Great Northern Semaphore' July 1926
- ItemGNSemaphoreVol3No8 - 'Great Northern Semaphore' August 1926
- ItemGNSemaphoreVol3No9 - 'Great Northern Semaphore' September 1926
- ItemGNSemaphoreVol3No10 - 'Great Northern Semaphore' October 1926
- 26 mais...