Track-Level., patent, August 25, 1908; (https://texashistory.unt.edu/ark:/67531/metapth514889/m1/3/: accessed June 21, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Track-Level., patent, August 25, 1908; (https://texashistory.unt.edu/ark:/67531/metapth514889/m1/3/: accessed June 21, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .