Rotary Drill, patent, January 6, 1903; (https://texashistory.unt.edu/ark:/67531/metapth509472/m1/1/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Rotary Drill, patent, January 6, 1903; (https://texashistory.unt.edu/ark:/67531/metapth509472/m1/1/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .