Mail Delivery Apparatus, patent, December 16, 1919; (https://texashistory.unt.edu/ark:/67531/metapth1257682/m1/1/: accessed June 22, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Mail Delivery Apparatus, patent, December 16, 1919; (https://texashistory.unt.edu/ark:/67531/metapth1257682/m1/1/: accessed June 22, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .