Oklahoma constitution
Article X: revenue and taxation
Section 10a

The proceeds of such levy shall be used by the county for creation, development, operation and maintenance of such public libraries and library services as are authorized by the Legislature. Nothing herein shall prohibit other levies for public libraries and library services or the use of other public funds for such purposes. All expenditures of the proceeds of such levies shall be made in accordance with laws heretofore or hereafter enacted concerning such libraries and library services. The provisions hereof shall be self-executing.