Ditch-Filling Machine, patent, August 9, 1921; (https://texashistory.unt.edu/ark:/67531/metapth1259180/m1/1/: accessed June 22, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Ditch-Filling Machine, patent, August 9, 1921; (https://texashistory.unt.edu/ark:/67531/metapth1259180/m1/1/: accessed June 22, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .