Tex. Tax Code § 151.339
The receipts from the sale, use, or rental of and the storage, use, or consumption in this state of taxable services are exempt from the tax imposed by this chapter, if:
(3) if notice of a contract or bid on which an exemption is to be claimed is given by the taxpayer to the comptroller within 60 days from the date this chapter takes effect.
The exemption provided by this section shall have no effect after September 30, 1987.
Added by Acts 1984, 68th Leg., 2nd C.S., ch. 31, art. 7, Sec. 18, eff. Oct. 2, 1984.