CITATOR: A tool that helps a researcher determine the status of a case, statute, or regulation.
A citator reports when a document is cited in some other more recent publication. With case law, legal citators indicate when a given case has been cited by a later case, and if so, what effect that later citation has on the original case. Any case you plan to rely on as precedent must be carefully updated using a legal citator.
Legal Research in a Nutshell, pp. 81-88 (Key Numbers & Digests)
Legal Research in a Nutshell, pp. 91-96 (Citators)
Key numbers are like the Dewey Decimal System for the Law. Like call numbers on the spines of library books, key number bring similar cases together.
Every Headnote in every case published by West (now ThomsonReuters) is assigned a Topic & Key Number. This designation brings together all of the cases on an issue.
To make it easier for the computer, the topics have all been assigned numbers. In the example below, the topic Eminent Domain has been assigned the number 148:
Eminent Domain 61
The picture of the key becomes the letter "k."
So the complete online key number reads: 148k61
Key Numbers are hierarchical--that is they are part of an outline. In this example, "In General" doesn't make sense unless you know that it is a sub-topic of "Taking for Private Use."
You may hear older attorneys talk about Digests. Digests are sets of books that publish headnotes by jurisdiction in key number order.
On WestlawNext, the Digest field will search both the headnotes and the key numbers.
Topics sometimes correspond to Encyclopedia topics. Vendor & Purchaser (having to do with the sale of real property) is both an AM JUR 2d topic and a Key Number Topic (400).
Backwards Citation is a list of the citations contained in the document you are starting with. In a college term paper it is called bibliography or resources. In legal writing it is called the Table of Authorities, that is a list of the cases, statutes and regulations that are the primary authority your arguments are based on.
Forward Citation is a list of the materials published since your document that refer back to it. These more recent documents may directly overrule your original doucment.
Reference Guide: KeyCite on WestlawNext
Reference Guide: Shepardizing on Lexis Advance
Reference Guide: BCite on BloombergLaw
Annotated Codes list cases, journal articles, ALR annotations and other useful references at the end of each section of a statute:
