Sinclair, Merle. [Letter from Merle Sinclair to T. N. Carswell - July 13, 1956], letter, July 13, 1956; (https://texashistory.unt.edu/ark:/67531/metapth1398160/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .