Liverpool, M. Heller. [Memorandum from M. Heller Liverpool, June 11, 1963], letter, June 11, 1963; (https://texashistory.unt.edu/ark:/67531/metapth1299463/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .