California Code, Education Code - EDC § 1770

(a) The county superintendent of schools may, with the approval of the county board of supervisors and the county board of education, agree with the county librarian to take over all existing contracts for supplementary books and other material adopted for the course of study between the school districts or community college districts and the county librarian entered into pursuant to Article 4 (commencing with Section 18130) of Chapter 2 of Part 11.  Thereafter, the county superintendent of schools shall generally perform the library services for the school districts or community college districts that were previously performed by the county library.

(b) After the above agreement has been entered into, the governing board of any district that had not yet joined the county library may enter into an agreement with the county superintendent of schools for the performance of school library services upon the terms and conditions fixed in the contracts or agreements.

(c) Whenever the county superintendent of schools performs school library services for any district, the provisions of Article 4 (commencing with Section 18130) of Chapter 2 of Part 11, so far as applicable, shall control.  The county superintendent of schools shall employ a librarian holding a valid credential authorizing services as a librarian issued by the Commission on Teacher Credentialing.  The county superintendent of schools shall also employ the assistants that may be necessary to carry on this service.  The cost of the salaries of the librarian and assistants, and the other necessary expenses of maintenance of the library, including necessary supplies, equipment, and books, may be paid from the county school service fund.