Switch-Locking Device., patent, March 11, 1919; (https://texashistory.unt.edu/ark:/67531/metapth1258694/m1/2/: accessed July 5, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Switch-Locking Device., patent, March 11, 1919; (https://texashistory.unt.edu/ark:/67531/metapth1258694/m1/2/: accessed July 5, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .