A. Emmett Bly, "Toll Gate System for the U.S.A." plan, Rare Books and Manuscripts, Indiana State Library
A. Emmett Bly, "Toll Gate System for the U.S.A." plan, Rare Books and Manuscripts, Indiana State Library https://archives.isl.lib.in.us//repositories/2/resources/4036 Accessed January 30, 2025.
