Acts 1965, 59th Leg., vol. 2, p. 317, ch. 722.

Amended by Acts 1981, 67th Leg., p. 809, ch. 291, Sec. 112, eff. Sept. 1, 1981; Acts 1993, 73rd Leg., ch. 900, Sec. 5.03, eff. Sept. 1, 1993.