[Letter from Roy E. Henderson to Harris L. Kempner, I. H. Kempner, III, H. L. Williams and Roy P. Bennett, December 18, 1974], letter, December 18, 1974; (https://texashistory.unt.edu/ark:/67531/metapth1211882/m1/1/: accessed June 28, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .