Research Strategy, Articles and Citation Guides

Legal Research Strategy

This guide is intended for graduate level students and staff at the Harvard University who are interested in conducting basic legal research but do not have online access to the Westlaw, Lexis Advance or Bloomberg Law databases, which are restricted to Harvard Law School affiliates. Westlaw can be used at the HLS library.

Start your research by reading a legal encyclopedia, handbook, treatise, and other book or article (often referred to as "secondary sources") before looking at the actual text of the law. Why?

  • Secondary sources will help you to identify the primary law (laws, regulations, and cases) that applies to topic.
  • Secondary sources provide an overview, summary, synthesis and explanation of the law as well as analysis and critique.
  • Secondary sources help you to identify subject headings, key numbers, and legal concepts and terms to help you search for how primary law materials.

To find a book, search in our catalog, HOLLIS. Elgaronline has academic handbooks and journals in law, management, public and social policies.

Harvard Law School Library, Secondary Sources guide explains and provides links to secondary sources. The American Jurisprudence 2nd (legal encyclopedia) can be searched within Nexis Uni.

Primary law is not binding in every jurisdiction. Cases can be overturned in the courts. Statutes and regulations can be repealed or expire. Use up-to-date secondary sources to see if the primary law is still in force.You can conduct a "cite check" or Shepardize a cite in a database like Nexis Uni to determine if a law, statute or regulation is still good law. Federal regulations can be checked using the Electronic Code of Federal Regulations (eCFR).  Learn how with the E-CFR tutorial.

Searching for Articles in Law Reviews

Nexis-Uni and HeinOnline are full-text databases. Indexes can be used to search by subject headings, title, author, and journal, and may also have some full-text but not for everything. The indexes differ in the number and types of documents indexed, links to full text, date range, search interface (EBSCO, Gale, and HeinOnline) and subject headings.  If you are new to legal research and these databases, save time and search more effectively by watching a video demo, reading the search tips or  "Libguide", or asking a librarian.

HeinOnline Law Journal Library also contains several indexes and finding tools, including the Current Index to Legal Periodicals, which indexes by fields or areas of law and the Index to Foreign Legal Periodicals.

Use advanced search to search by topic, title or citation. Enter a term in "Search by PathFinder Subject" to bring all items indexed under that term.  Alternatively, use Pathfinder subjects to browse subjects by text or interactive graphic. Pathfinder subjects also appears in search results.  How to Browse and Search with PathFinder video (about 5 min.)

Nexis Uni uses SmartIndexing Technology to tag news, business, company, corporate surveys, legislative documents, names, geographic location, and subjects by topics and use of a controlled vocabulary. Nexis Uni Top 10 Features and Tips

Search within American Jurisprudence 2d (AMJUR) legal encyclopedia.   From the main page of the database, click on the menu dropdown.  Select "All Sources." You should see  “American Jurisprudence 2d beside the search box. Enter search terms in the box.  You can also search and browse using the AMJUR Table of Contents.

General Legal Databases

These expansive databases include a combination of primary and secondary law resources.The terms "primary law" and "primary authority" in  refer to categories of legal texts (statutes and codes, cases, regulations, and treaties) created by legislative bodies, courts, and agencies that taken together are the legal authorities that constitute "the law." In most cases, you should start with secondary sources such as law review articles or books to help you identify important primary law. Search in HOLLIS for books on your legal topic.

Citation Guides

Legislative News & History

News & Tracking

Legislative History

US Laws, Regulations, Ordinances & Cases

Federal Laws & Regulations

Listing of what is available at govinfo and links to other legislative, executive and judicial process resources.  The Catalog of U.S. Government Publications (CGP), a finding tool for government publications (from July 1976 -present), includes records for print and content available on govinfo and links to govinfo for access to these publications.

States Laws and Regulations

For additional sources, visit the Harvard Law School Comparing State Laws and Constitutions research guide.

City/County Codes & Ordinances

There is no easy way to search all municipal codes at the same time. This HKS Library Fast Answer provides detailed instructions for locating municipal ordinances or codes in Nexis Uni. Please note that major metropolitan areas may have town, city and/or county ordinances that apply depending on what part of the metropolitan area you are researching. In some areas, you may have county and city codes that apply.

Search for reputable NGOs and think tanks in your policy area as they may have expert practitioners that monitor changes to state and local code. 

Other free resources that provide access to ordinances/codes are listed below: (links to county/local codes where available),

Case Law


Foreign & International Law



Foreign & International Law

Related Guides

Research Guides from other Harvard Libraries

Law Librarians at the Harvard Law Library have authored a large number of specialized legal research guides on topics of interest to members of the Harvard Law School community. They can be viewed at

Some introductory legal research guides are highlighted below:

Non-Harvard State Legal Research Guides

These guides will provide links to their own catalogs or login pages.  Check HOLLIS to see if the resources are available to access the content.