Brandenburg, E. G. [Letter from E. G. Brandenburg to C. C. Cox, March 10, 1923], letter, March 10, 1923; (https://texashistory.unt.edu/ark:/67531/metapth1243513/m1/1/: accessed July 7, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .