Drill Bit, patent, February 14, 1922; (https://texashistory.unt.edu/ark:/67531/metapth1259428/m1/1/: accessed June 21, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Drill Bit, patent, February 14, 1922; (https://texashistory.unt.edu/ark:/67531/metapth1259428/m1/1/: accessed June 21, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .