Texas. Legislature. Senate. 80th Texas Legislature, Regular Session, Senate Bill 1786, Chapter 1336, legislative document, June 15, 2007; (https://texashistory.unt.edu/ark:/67531/metapth155769/m1/1/: accessed November 18, 2018), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .