Music-Indicator., patent, July 4, 1911; (https://texashistory.unt.edu/ark:/67531/metapth514416/m1/3/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
Music-Indicator., patent, July 4, 1911; (https://texashistory.unt.edu/ark:/67531/metapth514416/m1/3/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .