Dubbing-Machine., patent, June 10, 1919; (https://texashistory.unt.edu/ark:/67531/metapth1257657/m1/3/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Dubbing-Machine., patent, June 10, 1919; (https://texashistory.unt.edu/ark:/67531/metapth1257657/m1/3/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .