Montalbo, Philip J. [Letter from Philip J. Montalbo to Roy M. Hofheinz - 1965-04-24], letter, April 24, 1965; (https://texashistory.unt.edu/ark:/67531/metapth248808/m1/1/: accessed July 5, 2020), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .