Dallas (Tex.). Police Department. [Report to W. P. Gannaway by F. A. Hellinghausen and P. M. Parks, February 13, 1964 #1], report, February 13, 1964; (https://texashistory.unt.edu/ark:/67531/metapth338314/m1/1/: accessed May 20, 2019), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .