Okla. Stat. tit. 19, § 957

An "employee", as used Sections 951 through 962 of this title, shall include the elected or appointed salaried officials and regular full-time salaried employees of a county, and shall also include regular full-time employees of the county board of library trustees, county employees whose salaries are paid in whole or in part from the court fund of such county, employees of county circuit engineering districts, and employees of any public trust created pursuant to law in which the county is the sole beneficiary of the public trust, if approved by the board of county commissioners.