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Legal Research Fundamentals

Secondary Sources

Start with a secondary source!


There are many different reasons to use secondary sources. Your specific research task will determine the type of resource you want to consult.

Below we have provided information about the many different types of secondary sources. When possible, we try to provide guidance regarding the best way to access each source. But remember, using secondary sources is almost always part of a bigger picture research task. For that reason, we recommend you always ask yourself:

  1. What do I ultimately need to find? What type of secondary resource will best provide this type of information. 

  2. What is the fastest, most efficient way to find the information I need within that type of resource? 

Legal Dictionaries

Legal dictionaries can be very useful for determining the meaning of a legal term. They also with provide citations to seminal cases, Westlaw Key Numbers, and other references. Legal dictionaries can also be very helpful for foreign legal research. 


Legal encyclopedias are excellent places to start when you know very little about the area of law you are dealing with, and you want to get a basic overview. They are also great for providing background information, and for identifying many of the key issues in a particular area of law. Encyclopedias generally have the word "encyclopedia" or "jurisprudence" in their title.

American Law Reports

American Law Reports are wonderful resources if you are hoping to find in-depth coverage of a particular issue, with citations to the relevant statutes and key cases. ALR annotations only cover certain issues, however: if you find an updated ALR annotation related to your issue, you're in luck! Otherwise, look for a similar issue, or move on to another source. 

American Law Reports can be searched in full text on both Lexis and Westlaw

Searching for Specific Titles (Looking for a Book)

When you have been tasked with locating a specific title, whether in print or an electronic form, the fastest way to find it is likely by using a library catalog. 

Locating Useful Treatises

Treatises provide comprehensive, in-depth examinations of a particular area of law.

For many areas of law, there are one or two preeminent treatises. Georgetown Law Library's Treatise Finder and Harvard Law Library's Legal Treatise by Subject are good guides to help identify the leading titles for dozens of different legal topics.

When searching individual treatises, it often is best to browse the Table of Contents, consult the index, or do a full-text search. 

Practice Materials

To locate useful practice materials, check out the resources and techniques noted in the Treatises section above, keeping your eye out for the word "practice" in the title. Additionally, several databases provide legal practice tools. 

CLE and Bar Materials

Continuing Legal Education (CLE) materials can be wonderful sources of information that might not otherwise be included in a treatise, practice guide, law review, or ALR annotation. Use them if you are looking for guidance or analysis on a specific practical matter, attorney ethics, or a recent development in the law. 

You can often locate bar association or CLE materials from their websites (often by running a Google search for the issue and the term "CLE" or the name of the jurisdiction's bar association, and narrowing to a particular filetype, such as pptx or pdf). However, in many instances these CLE materials will be behind a paywall. Biddle Law Library holds many CLE materials from the Pennsylvania Bar Institute in our collection--please see a Reference Librarian for more information.

CRS Reports

The Congressional Research Service (CRS) provides policy and legal analysis to committees and Members of both the House and Senate, regardless of party affiliation. CRS Reports can provide useful analyses of legal topics of interest to lawmakers and legal researchers, and include citations to relevant statutes and any major cases that have recently changed the law (e.g., recent Supreme Court cases). CRS Reports also address key administrative agency actions, where appropriate, and international agreements.  There are several ways to locate CRS reports: 

Searching Journals, Legal Periodicals, and Other Scholarship

There are many different ways to locate relevant articles related to any legal subject. You can do full text searching in Lexis, Westlaw, Google Scholar, Biddle Law Library's Search Center catalog, or a number of other databases (for useful non-legal databases, see the Non-Legal tab). 

You may also be able to more efficiently locate material by searching specific fields in an advanced search. This will allow you to search for articles with specific words in the title or summary, or by a certain other. 

We highly recommend using a legal periodical index. Search by subject or keyword to locate articles that fall under your topic.

Legal Newspapers, Blogs, Other Current Awareness

These resources are useful when you are looking for:

  • Information about a very recent development in the law
  • News about particular attorneys, clients, judges, etc.
  • Informal, current academic discussions
  • Guidance and insight on particular issues (Certain areas of law have particularly robust news and online offerings.)

There are several ways to locate current awareness tools. Some of the key links are listed below. 

The search functionality of these resources varies. For standalone websites, you can often do a better search by using Google: search your terms + inurl:. If the resource is available via Bloomberg, Lexis, or Westlaw, take advantage of their more advanced search functions to locate what you are looking for.