[Letter from Isaac H. Kempner to the Southern Pacific Ticket Office, May 10, 1944], letter, May 10, 1944; (https://texashistory.unt.edu/ark:/67531/metapth1451768/m1/2/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .