34 Tex. Admin. Code § 101.7
The director is authorized to require submission of documents reasonably related to establishment of a claimed right to benefits. These documents include but are not limited to birth certificates; marriage licenses; divorce decrees; letters of guardianship; letters testamentary or letters of administration; death certificates; relevant court orders; sworn statements of witnesses and attending physicians; autopsy reports; and sworn statements of the claimant or of others having personal knowledge of relevant facts. Except upon good cause being shown, failure to submit all required documents within four months of the date specified by the member as his or her effective retirement date will invalidate the application for retirement (service or disability) for all purposes. Thereafter, a new application must be submitted and a new retirement date chosen in accordance with § 101.6 of this title (relating to Time for Filing of Retirement Applications).
34 Tex. Admin. Code § 101.7