Revolving-Cutter Rotary Boring-Drill., patent, November 2, 1915; (https://texashistory.unt.edu/ark:/67531/metapth857808/m1/1/: accessed June 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
Revolving-Cutter Rotary Boring-Drill., patent, November 2, 1915; (https://texashistory.unt.edu/ark:/67531/metapth857808/m1/1/: accessed June 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .