For example, Sutherland s Statutory Construction was first published in 1891 and is now in its fifth edition and is kept up to date by revised volumes, pocket parts, and supplementary pamphlets. Law reviews Law schools usually publish reviews and these lengthy articles provide excellent background information on particular topics, cases and statutes. Shepard s, Westlaw, and Lexis-Nexis provide varying levels of depth in ascertaining whether any cases, statutes, regulations, and law reviews affect a particular case. This is very useful in determining whether a case has been overruled, modified, or treated in a meaningful way. Supplemental materials are rarely persuasive, except in certain situations when an area of law is too cryptic to rely solely on primary and secondary materials.
Treatises are more authoritative than any other supplementary source.
Jurisdiction plays a role in determining how relevant a source is. This can get tricky because all three branches of the federal government have state and local counterparts. Without going into unnecessary detail, the general rule is that a trial court is required to accept its circuit court s opinions and those of the Supreme Court. They also generally accept another trial court s decision within the same circuit. Opinions from other circuits or levels of government may be persuasive, but are not binding.