Calculating Device., patent, November 24, 1885; (https://texashistory.unt.edu/ark:/67531/metapth171141/m1/1/: accessed April 27, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
Calculating Device., patent, November 24, 1885; (https://texashistory.unt.edu/ark:/67531/metapth171141/m1/1/: accessed April 27, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .