Tex. Gov't Code § 804.002

This subchapter and Subchapter C apply to each statewide retirement system and to the optional retirement program governed by Chapter 830. This subchapter and Subchapter C also apply to each other public retirement system for which the board of trustees of the system elects to adopt the provisions of this subchapter and Subchapter C. An election under this section must be by order or resolution and need not set out the text of this subchapter or Subchapter C. A board of trustees may not elect to adopt only this subchapter or Subchapter C.