* {{Kilde bog|titel=Destination Loop: The Story of Rapid Transit Railroading in and around Chicago|efternavn=Cudahy|fornavn=Brian J.|år=1982|udgiver=S. Greene Press|sted=Brattleboro, VT|isbn=978-0-8289-0480-3|url=https://archive.org/details/destinationloops00cuda}}
* {{Kilde bog|titel=Robber Baron: The Life of Charles Tyson Yerkes|efternavn=Franch|fornavn=John|år=2006|udgiver=University of Illinois Press|sted=Urbana|isbn=978-0-252-03099-4|url=https://archive.org/details/robberbaronlifeo00fran}}
* {{Kilde bog|efternavn=Reardon|fornavn=Patrick T.|url=https://books.google.com/books?id=Z5xSzQEACAAJ|titel=The Loop: The L Tracks That Shaped and Saved Chicago|udgiver=Southern Illinois University Press|år=2020|isbn=978-0-8093-3810-8|sprog=en}}
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