Public law libraries provide access to primary legal sources (statutes, cases, and regulations) and secondary sources (professional reference books, form books, and self-help books) used in legal matters. In most U.S. states, public law libraries are part of the trial court system, a department of the state or county government, or an independent local government agency managed by a board of trustees. Public law libraries serve several user groups with different information needs: judges and their support staff, attorneys in all types of practice, and the general public.