 State agencies promulgate rules and regulations (sometimes called administrative law) in the "Register of Ohio", which are in turn codified in the "Ohio Administrative Code" (OAC).Ohio's legal system is based on common law, which is interpreted by case law through the decisions of the Ohio Supreme Court, Ohio District Courts of Appeals, and trial courts, which are published in the "Ohio Official Reports".Counties, townships, and municipalities may also promulgate local ordinances.