[Letter from Leonard R. Sussman to Mrs. I. Ernest Burka, May 18, 1962], letter, May 18, 1962; (https://texashistory.unt.edu/ark:/67531/metapth1496722/m1/4/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .