Texas. Legislature. House of Representatives. 83rd Texas Legislature, Regular Session, House Bill 1768, Chapter 951, legislative document, June 14, 2013; (https://texashistory.unt.edu/ark:/67531/metapth438621/m1/1/: accessed November 19, 2018), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .