[Letter from William S. DuBois to Harris L. Kempner, September 26, 1960], letter, September 26, 1960; (https://texashistory.unt.edu/ark:/67531/metapth1425038/m1/1/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .