Johnson, T. P. [Letter from T. P. Johnson to Prince and Plosser Air School, August 31, 1942], letter, August 31, 1942; (https://texashistory.unt.edu/ark:/67531/metapth862365/m1/2/: accessed February 23, 2020), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .