Tex. Educ. Code § 107.62

In payment for the erecting and equipping of dormitories and improvements, the board may issue its obligations in the amount and on the terms deemed advisable by the board. As security the board may pledge the income from the dormitories and improvements erected or from other dormitories owned by the system, as well as all other revenue derived by the system from other sources, except revenue derived by means of appropriations made for a specific purpose by the legislature.