Standing Valve, patent, September 21, 1920; (https://texashistory.unt.edu/ark:/67531/metapth1259024/m1/1/: accessed June 22, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Standing Valve, patent, September 21, 1920; (https://texashistory.unt.edu/ark:/67531/metapth1259024/m1/1/: accessed June 22, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .