Olson, John Victor. [Letter from John Victor Olson to Todd Bradford Willis, May 28, 1975], letter, May 28, 1975; (https://texashistory.unt.edu/ark:/67531/metapth599753/m1/1/: accessed May 24, 2019), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .