[Letter from Harris Leon Kempner to Schwabach, Kempner, Perutz, Inc., May 16 1967], letter, May 16, 1967; (https://texashistory.unt.edu/ark:/67531/metapth1266795/m1/1/: accessed June 20, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .