Underreamer., patent, February 9, 1914; (https://texashistory.unt.edu/ark:/67531/metapth859510/m1/1/: accessed April 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
Underreamer., patent, February 9, 1914; (https://texashistory.unt.edu/ark:/67531/metapth859510/m1/1/: accessed April 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .