Steam and Air Valve Operator., patent, February 12, 1907; (https://texashistory.unt.edu/ark:/67531/metapth509288/m1/1/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Steam and Air Valve Operator., patent, February 12, 1907; (https://texashistory.unt.edu/ark:/67531/metapth509288/m1/1/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .