[Letter from Harris L. Kempner to Dr. Marion J. Levy, Jr., May 22, 1964], letter, May 22, 1964; (https://texashistory.unt.edu/ark:/67531/metapth1421006/m1/1/: accessed June 20, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .