Texas. Legislature. House of Representatives. 80th Texas Legislature, Regular Session, House Bill 280, Chapter 1168, legislative document, 2007-04/2007-06; (https://texashistory.unt.edu/ark:/67531/metapth155115/m1/1/: accessed November 20, 2018), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .