Kempner, Isaac Herbert, III. [Letter from I. H. Kempner, III to Walter Rathjen, October 16, 1975], letter, October 16, 1975; (https://texashistory.unt.edu/ark:/67531/metapth1211787/m1/1/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .