Railroad Archives Online
- FondoD0046 - Andrew Klamka Collection
- Serie003 - Great Northern Railway Company (U.S.)
- Sottoserie004 - Library
- 002 - Periodicals
- 37 in più...
- Unità documentariaGNSemaphoreVol4No2 - 'Great Northern Semaphore' February 1927
- Unità documentariaGNSemaphoreVol4No3 - 'Great Northern Semaphore' March 1927
- Unità documentariaGNSemaphoreVol4No4 - 'Great Northern Semaphore' April 1927
- Unità documentariaGNSemaphoreVol4No5 - 'Great Northern Semaphore' May 1927
- Unità documentariaGNSemaphoreVol4No6 - 'Great Northern Semaphore' June 1927
- Unità documentariaGNSemaphoreVol4No7 - 'Great Northern Semaphore' July 1927
- Unità documentariaGNSemaphoreVol4No8 - 'Great Northern Semaphore' August 1927
- Unità documentariaGNSemaphoreVol4No9 - 'Great Northern Semaphore' September 1927
- Unità documentariaGNSemaphoreVol4No10 - 'Great Northern Semaphore' October 1927
- 14 in più...