American Express Company. [Letter from American Express Company to Daniel W. Kempner, May 11, 1950], letter, May 11, 1950; (https://texashistory.unt.edu/ark:/67531/metapth1349401/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .