Texas. Legislature. House of Representatives. 80th Texas Legislature, Regular Session, House Bill 2723, Chapter 1073, legislative document, 2007-05/2007-06; (https://texashistory.unt.edu/ark:/67531/metapth155096/m1/1/: accessed November 20, 2018), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .