Horst, Henry W. [Letter from Henry W. Horst to William Hagen, January 30, 1930], letter, January 30, 1930; (https://texashistory.unt.edu/ark:/67531/metapth606482/m1/1/: accessed April 26, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .