[Letter from I. H. Kempner to Dan Oppenheimer, December 17, 1962], letter, December 17, 1962; (https://texashistory.unt.edu/ark:/67531/metapth1472589/m1/1/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .