A contract may be defined as an agreement between private parties that creates obligations enforceable by law. Contract law is governed by state statutory law and common law as well as private law (the terms of the agreement between private parties). Most of the common law principles of contract law come from the Restatement of Contracts, 2d. Additionally, nearly every state's legislature has adopted the Uniform Commercial Code. Legal researchers should consult the secondary authorities page to be directed towards resources that may help a researcher determine whether an issue is a common law issue or whether an issue involves researching state statutes as well as cases. This guide compiles primary authority sources and then directs the researcher to secondary sources. This guide also features Study Aids that students may find useful to supplement learning in law school courses.