[Letter from George G. Kirstein to Harris L. Kempner, June 7, 1957], letter, June 7, 1957; (https://texashistory.unt.edu/ark:/67531/metapth1419348/m1/1/: accessed July 9, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .