[Letter from Blume System Tree Experts to D. W. Kempner, June 23, 1944], letter, June 23, 1944; (https://texashistory.unt.edu/ark:/67531/metapth1328955/m1/2/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .