Amy Balkin, “In Transit”, CabSpotting, http://cabspotting.org/projects/intransit/; “FAQ”, CabSpotting, http://cabspotting.org/faq.html

“History of Railroads and Maps”, Library of Congress, 1998, http:// memory.loc.gov/ammem/gmdhtml/rrhtml/rrintro.html; Olivier Zunz, Making America Corporate (London: University of Chicago Press, 1990).