Treatises are narrative explanations of case law, statutes and regulations by named authors. They tend to be updated infrequently (1 or 2 times a year) or not at all.

Looseleafs generally contain primary legal sources (case law, statutes, and regulations) and secondary sources (news and commentary on recent developments in state and federal courts, legislatures, and administrative agencies). They are typically written and compiled by the publisher's editorial staff and are updated more frequently (weekly, biweekly, or monthly).