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Basics of Legal Research: Secondary Sources

Introduction to the basics and fundamentals of legal research, including information on understanding citations, and the difference between primary and secondary sources.

What Are Secondary Sources?

Secondary sources help the researcher to identify and understand the law. Though generally not cited as legal authority, courts will sometimes use them to help explain legal terms or ideas. They include legal dictionaries and encyclopedias, journal articles, books, treatises, practice aids, self-help materials, and finding tools.

It is easier and generally more effective for a researcher to consult a secondary source to read about key statutes, regulations, and cases governing a particular area of law, e.g., family law, probate law, employment law, criminal law, before attempting to identify, locate and analyze those same resources using indexes for codes and regulations and digests for cases.

Certain secondary sources are available online via subscription to databases such as Westlaw and LexisNexis. Louisiana colleges and universities, including law schools, and public libraries may provide access to popular legal dictionaries via subscription to academic and public-access versions of Westlaw and LexisNexis under the Secondary Sources or Legal Reference sections of those databases.

Secondary Sources

Legal dictionaries define terms that are unique to the practice of law. Legal dictionaries are available in print and online.


Black’s Law Dictionary is the most well-known legal dictionary and is often cited by courts when addressing the meaning of particular legal terms. A legal thesaurus such as Ballentine’s Thesaurus for Legal Research & Writing or Burton’s Legal Thesaurus can help researchers find terms to search print indexes and formulate online keyword searches. In addition, Prince's Bieber Dictionary of Legal Abbreviations is a great tool for deciphering common legal abbreviations and acronyms used in a variety of legal documents.



Free legal dictionaries and glossaries are also available on the Internet. Examples include Merriam-Webster’s Dictionary of Law through FindLaw and Nolo’s Plain-English Law Dictionary















The Louisiana State Bar Association also provides a guide explaining legal terms and procedures in Louisiana

Additional Resources:

Legal encyclopedias summarize the law by topic and are available in print and online.


The two legal encyclopedias most widely used by lawyers are American Jurisprudence (Am. Jur.) and Corpus Juris Secundum (C.J.S.). These legal encyclopedias are usually found in law libraries but can also be found in some universities and colleges. They contain extensive footnotes to the law and secondary sources and are updated annually by pocket parts. The Louisiana Civil Law Treatise is similar to an encyclopedia but more detailed and specific to Louisiana law.



Legal encyclopedias written for non-lawyers, such as West’s Encyclopedia of American LawGale Encyclopedia of Everyday Law, and Nolo’s Encyclopedia of Everyday Law are available in many public and academic libraries.


The legal encyclopedias mentioned above are available online through subscription databases.  Cornell’s WEX is a comprehensive legal encyclopedia available on the Internet for free.



Law reviews and legal journals are published by law schools. Articles are written by law professors, attorneys, and law students.

 Law reviews, such as Louisiana Law Review or Tulane Law Review, address a wide range of topics, while journals tend to focus on specific areas of law, e.g., Loyola Journal of Public Interest Law and Journal of Race, Gender and Poverty from Southern. Many law schools publish both types.

State bar journals and magazines, such as Louisiana Bar Journal, are published by state bar associations and address a wide range of legal issues within a particular state. Articles are often written by attorneys, law professors, and other practitioners. Law review, journal, and state bar articles are available in print and online, by subscription and on the free web.


Law libraries carry print versions of law reviews and journals from across the country. 


Law libraries and academic libraries subscribe to online databases that contain the full text of law review and journal articles, such as HeinOnline. HeinOnline's collection includes over 2,000 law reviews and journals, often from the beginning of the journal's publication until the present. Articles are available in an easy-to-read PDF format.

Law schools across the country are beginning to support open access by making their law reviews and journals available via the Internet. Free online databases that allow researchers to search online journals include ABA’s Free Full-Text Online Law Review/Law Journal Search Engine and Google Scholar’s Advanced Search for legal opinions and journals.

Additional Resources:

Often, the easiest way for a non-lawyer to learn about a legal topic is to locate a current book on the topic— preferably one written for the layperson. Law libraries carry books with varying levels of difficulty and coverage, from short, paperback nutshells to multi-volume treatises. The Louisiana Pro Bono Desk Manual is available in full for free online and covers many topics that often affect self-represented litigants. The Law Library of Louisiana's catalog is searchable online as are those of academic and public libraries across the state.

A treatise is a reference book that provides in-depth coverage of a particular legal topic, often written by the leading scholar in that area of law.

The Louisiana Civil Law Treatise series covers many of the most common legal topics with detailed explanations, including references to the applicable law. Examples include treatises on tort law and the law of obligations.