A.R.S. § 11-913

Funds of the county free library district, whether derived from taxation or otherwise, shall be deposited with the county treasurer. They shall constitute a separate fund, called the county free library district fund, and shall be used for the county free library. Each claim against the county free library district fund shall be authorized and approved by the county librarian or, in his absence from the county, by his assistant. Claims shall be approved and paid in the same manner as other claims against the county.