Digests organize thousands of cases and points of law by subject. There are different publishing systems for digests, such as West and Lexis. Digests can be used by looking up topics in the index or using a relevant case's headnote and key number to find other cases on that point of law. Specifically, if a case is found that is on the correct topic, the headnote or topic and key number identifies the legal issue and allows the user to look it up in the digest.