34 Tex. Admin. Code § 25.45
Members who claim unreported service or compensation after the school year in which it was received and for whom the employer has not requested a waiver as provided in § 25.28(g) of this title (relating to Payroll Report Dates), must verify the claim on a form prescribed by the Teacher Retirement System and must present such evidence as the staff of the system may require to provide clear and convincing proof of the existence and amount of such service or compensation, such as a copy of the minutes of the governing board of the employing institution, copies of any written contracts between the member and the employer, a verified statement by the employer of the reasons why such service or compensation was not reported earlier, and copies of income tax documents showing that the compensation was reported as income for the member. Except as provided in § 25.26(a) of this title (relating to Annual Compensation Creditable for Benefit Calculation) for the calculation of a member's annual compensation in the school year in which the member retires, in no event shall verification, salary reports, or member contributions for additional compensation or service credit be accepted after a member has retired from the system and the first monthly annuity payment has been issued, after the effective date of a member's participation in the Deferred Retirement Option Plan, or after the payment of a death benefit. The cost for unreported service or compensation shall be as provided in § 25.43 of this title (relating to Cost for Unreported Service or Compensation).
34 Tex. Admin. Code § 25.45