The origins from which particular positive laws derive their authority and coercive force. Such are constitutions, treaties, statutes, usages, and customs. In another sense, the authoritative or reliable works, records, documents, edicts, etc. to which we are to look for an understanding of what constitutes the law. Such, for example, with reference to the Boman law, are the compilations of Justinian and the treatise of Gains; and such, with reference to the common law, are especially the an- cient reports and the works of such writers as Bracton, Littleton, Coke, “Fleta,” and others.
TLD Example: One of the original sources of law in the United States was English common law.