A case is the published decision of a court. Cases are published in "reporters." A reporter may cover one court (for example, California Reports covers California Supreme Court cases), or several courts (for example, West's California Reporter covers states in the Pacific Region and includes both State Supreme Court cases and some State Appellate Court cases.
Roe v. Wade, 410 U.S. 113, 93 S.Ct. 705, 35 L.Ed.2d 147 (1973).
Roe v. Wade is the case name.
This case can be found in volume 410 of the reporter called United States Reports on page 113.
The additional information after the page number are parallel citations which we will discuss below.
Roe v. Wade was decided in 1973.
If a citation wants to point their reader to a specific page or pages, a pinpoint citation (often called a "pincite"), must be used. In the example below, the pincite refers the reader to page 531.
Kleppe v. New Mexico, 426 U.S. 529, 531 (1976).
Cases are often found in more than one reporter. There is an "official" reporter, the one published or sanctioned by the court. The official reporter can be found by consulting the local rules, the Bluebook or ALWD. In addition to official reporters, there are other reporters which have also cited the case.. The official reporter is cited first, and is followed by "parallel citations", if the case can be found in other reporters. An example of a citation with an official reporter and a parallel citation is:
Pledger v. Halvorson, 324 Ark. 302, 921 S.W.2d 576 (1996).
To ensure that a particular case is still valid or good law, you must Shepardize (on Lexis) or Key-Cite (on Westlaw) the original case. These services report the subsequent history of each published case (for instance, whether the case has been overturned or reversed), and also cites authorities that have subsequently relied on the case.
Not all cases are published. Especially at the federal level, the majority of cases simply affirm an existing point of law, or are about a matter so minor that it is not worth publishing. Although unpublished cases may be found, in California jurisdictions, you may not cite to them.