[Letter from Harris L. Kempner to Mr. Marion J. Levy, Jr., March 13, 1957], letter, March 13, 1957; (https://texashistory.unt.edu/ark:/67531/metapth1419211/m1/1/: accessed July 10, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .