Valve-Spring Lifter., patent, June 18, 1918; (https://texashistory.unt.edu/ark:/67531/metapth1259284/m1/3/: accessed June 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Valve-Spring Lifter., patent, June 18, 1918; (https://texashistory.unt.edu/ark:/67531/metapth1259284/m1/3/: accessed June 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .