Railroad Archives Online
- ArquivoD0046 - Andrew Klamka Collection
- Série003 - Great Northern Railway Company (U.S.)
- Subsérie004 - Library
- 002 - Periodicals
- 37 mais...
- ItemGNSemaphoreVol4No2 - 'Great Northern Semaphore' February 1927
- ItemGNSemaphoreVol4No3 - 'Great Northern Semaphore' March 1927
- ItemGNSemaphoreVol4No4 - 'Great Northern Semaphore' April 1927
- ItemGNSemaphoreVol4No5 - 'Great Northern Semaphore' May 1927
- ItemGNSemaphoreVol4No6 - 'Great Northern Semaphore' June 1927
- ItemGNSemaphoreVol4No7 - 'Great Northern Semaphore' July 1927
- ItemGNSemaphoreVol4No8 - 'Great Northern Semaphore' August 1927
- ItemGNSemaphoreVol4No9 - 'Great Northern Semaphore' September 1927
- ItemGNSemaphoreVol4No10 - 'Great Northern Semaphore' October 1927
- 14 mais...