Upton, William F. [Letter from William F. Upton to A.L. Matlock, September 7, 188?], letter, 188X-09-07; (https://texashistory.unt.edu/ark:/67531/metapth186882/m1/1/: accessed July 8, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .