[Letter from Harris L. Kempner to Dr. Frank L. Boyden, July 19, 1956], letter, July 19, 1956; (https://texashistory.unt.edu/ark:/67531/metapth1418988/m1/1/: accessed June 25, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .