Skip to Main Content

Law and Legal Research

This guide provides information resources to support legal research

Getting Started

General Introduction to Legal Research

Legal materials come from different authorities, in different forms, and cover a variety of subjects.  This guide will break these materials down as follows:

  • jurisdictions - federal, state, tribal, and local governments and their component branches and administrative agencies.
  • formats/sources - cases, statutes, constitutions, treaties, regulations, policies, etc.
  • subjects - health policy, criminal justice, philosophy, literature, etc.

Formats and Sources

Judges preside over civil cases between private parties or between state entities and individuals for violating criminal laws.  The opinions they write are a source of law that comes from the court system, the judicial branch of government.  Together, these judicial opinions form a body of common law that is precedent that courts are bound to follow in future cases.  The federal courts and the state courts each have three levels: trial courts, appellate courts, and supreme courts.  Opinions are published in reporters and digests which are divided by state, region, or subject matter.  Libraries may still have reporters and digests on the shelves, but online databases are now the trusted source for case law. 

A quick note on citations: most case citations refer first to the parties, then the volume of the reporter, then the name of the reporter (or other publisher of the case), and finally the page number in that volume that the case falls on.  In Westlaw, a legal database referenced below, you can find a case by entering, for example, 531 U.S. 98, which will take you to the 531st volume of the United States Reports, at page 98.

Case law research is sometimes complicated by subsequent, related cases with inevitably different legal issues, parties, and facts before the court.  Courts that review the opinions of lower courts sometimes overturn a decision, entirely or just in part, or they may remand the case back down to the lower court to be heard and decided again.  Citators are used to update legal research by linking these trial, appellate, and supreme court cases together in a web of law that makes up the common law.  As with reporters, citators are most frequently accessed online.


Depending on the context, the terms "law," "legislation," and "statutes" are used to refer to bills that are drafted and approved by legislative bodies and signed by an executive (a Governor or the President).  Session laws are published at the end of a legislative session (usually a year) and list legislation in chronological order.  Codes contain legislation that is now in force, arranged by subject in "titles" or "parts."  Each new edition of a code includes amendments and deletes repealed legislation.  Annotated codes are extremely efficient research tools because they are up-to-date and include annotations that point to other legal authorities and formats, such as the legislative history surrounding a law, prior versions of the law, state and federal cases that have interpreted the legislation, regulations that give details about the application of the legislation, and relevant secondary sources such as Restatements of Law. 

Statute citations are less standardized than case citations.  Legislation can be found by using a public law numbertitle and section numbers, or a popular name.  Common citations to Obamacare, for example, are P.L. 111-148, which is found in the code at 42 U.S.C. ("United States Code") 18001, under the popular name the "Patient Protection and Affordable Care Act."  ProQuest Congressional supplements the annotated codes that are available in Westlaw and NexisUni, and helps get a fuller picture of the life of a bill, from proposal, consideration and amendment in committees, to enactment.

Administrative agencies like the Environmental Protection Agency and the Wisconsin Department of Children and Families issue detailed regulations and make decisions in hearings that have the force of law.  Just as statutes are first published chronologically as session laws, administrative rules are published in order in the Federal Register, and then later arranged by subject ("codified") in the Code of Federal Regulations, which is organized into a helpful Index in Westlaw and NexisUni. There are corresponding state-level codes of regulations available, as well.  

Example: COVID-19

COVID-19 Example: Sources and Authorities

The global novel coronavirus pandemic is a timely example of a legal research issue that can be usefully organized by authorities, formats, and sub-topics. 

For example: How are unemployment benefits administered by states?  Who has the power to close restaurants to prevent the spread of a communicable disease? 

 - Authority: You're mostly looking for state- and local-level orders and regulations, usually "executive orders" and state health department regulations and orders.  In Wisconsin, a heated debate around how the Department of Health Services decided to address the spread of COVID-19 culminated in a Supreme Court case, Wisconsin Legislature v. Palm, 942 N.W. 2d 900 (May 13, 2020).  Further, think through which policy organizations have a vested interest in protecting their specific constituents: small businesses, the incarcerated, older adults, supply-chain labor union members, educators, etc.

 - Source/Format: Although a few cases would explore the legal issues related to the coronavirus, most materials will be published by administrative agencies.  These regulations are less formally organized than cases and statutes, so expect to spend a little more time exploring agency websites and legal databases to find a regulation related to your question or research problem. The resources listed below are good starting points, especially the collection from the Wisconsin State Law Library.

Sources and Formats of Law

Breakdown of Subjects, Authorities, and Formats/Sources

Legal topic


Federal or State?


Primary Source of law




Bankruptcy Federal  Statute Some exemptions are covered by state statute
Constitutional law Federal and State Case law interpreting government action (not private parties)  
Contract issues State Case law  
Criminal law State (mostly) or Federal Statute Criminal procedure is written into law by statutes, but governed also by state and federal constitutional law
Divorce and custody State Statute  
Employment State and Federal Statute  
Health State and Federal Statute The Social Security Act, for example, includes Medicare legislation.
Housing Federal (mostly) or State    
Intellectual property (copyright and patent) Federal Statute Almost all other property rights are determined under state law.
Landlord-tenant State Statute  
Torts (including accidents) State Case law, some statutes  
Inheritance law State Statute Laws about inheritance are often called "probate" codes.


This table has been adapted from Healy, Paul (2014). Legal reference for librarians. American Library Association.