Railroad Archives Online
- FondoD0046 - Andrew Klamka Collection
- Serie003 - Great Northern Railway Company (U.S.)
- Sottoserie004 - Library
- 002 - Periodicals
- 16 in più...
- Unità documentariaGNSemaphoreVol2No5 - 'Great Northern Semaphore' May 1925
- Unità documentariaGNSemaphoreVol2No6 - 'Great Northern Semaphore' June 1925
- Unità documentariaGNSemaphoreVol2No7 - 'Great Northern Semaphore' July 1925
- Unità documentariaGNSemaphoreVol2No8 - 'Great Northern Semaphore' August 1925
- Unità documentariaGNSemaphoreVol2No9 - 'Great Northern Semaphore' September 1925
- Unità documentariaGNSemaphoreVol2No10 - 'Great Northern Semaphore' October 1925
- Unità documentariaGNSemaphoreVol2No11 - 'Great Northern Semaphore' November 1925
- Unità documentariaGNSemaphoreVol2No12 - 'Great Northern Semaphore' December 1925
- Unità documentariaGNSemaphoreVol3No1 - 'Great Northern Semaphore' January 1926
- 35 in più...