Thomsen, Charles H. [Letter from Charles H. Thomsen to Toby P. Hernandez - 1966-04-04], letter, April 4, 1966; (https://texashistory.unt.edu/ark:/67531/metapth222443/m1/1/: accessed April 30, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .