Bertig, Joseph R. [Letter from Joseph R. Bertig to D. W. Kempner, July 10, 1950], letter, July 10, 1950; (https://texashistory.unt.edu/ark:/67531/metapth1349529/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .