A more thorough explanation:

Federal Supplement

The Federal Supplement is a legal reference book that contains court decisions from the United States federal district and appellate courts. It is abbreviated as F.Supp. and is often used by lawyers and judges to research and cite legal cases.

One example of a case that might be found in the Federal Supplement is Smith v. Jones, 123 F.Supp.2d 456 (D. Mass. 2001). This citation tells us that the case was heard in the United States District Court for the District of Massachusetts in 2001 and was published in volume 123 of the Federal Supplement, second series, starting on page 456.

Another example is United States v. Johnson, 789 F.Supp. 1234 (E.D. Cal. 1992). This citation tells us that the case was heard in the United States District Court for the Eastern District of California in 1992 and was published in volume 789 of the Federal Supplement, starting on page 1234.

The examples illustrate how the Federal Supplement is used to cite legal cases. Each citation includes the name of the case, the volume and series of the Federal Supplement where it was published, the court where the case was heard, and the year of the decision. Lawyers and judges use these citations to find and reference legal cases when arguing their own cases in court or conducting legal research.