Kempner, Harris Leon. [Letter from Harris L. Kempner to Mr. Ross Whistler, May 13, 1957], letter, May 13, 1957; (https://texashistory.unt.edu/ark:/67531/metapth1419385/m1/1/: accessed July 7, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .