: Retirement; Defined Contribution Retirement Plan for Teachers Act; trust; plan assets; Teachers' Retirement System of Oklahoma; certified personnel; election; defined benefit plan; service credit; terms; Board of Trustees; operating plan document; duties; policies; competitive bid process; contract; report; contribution rate; participants; employers; vesting; individual account; investment menu; alternative distribution forms; surviving spouse or beneficiary; minimum salary schedule; codification; effective date.