Behnken, J. W. [Letter from J. W. Behnken to R. Osthoff, July 8, 1926], letter, July 8, 1926; (https://texashistory.unt.edu/ark:/67531/metapth606439/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .