The three most common types of legal documents that legal researchers use, in addition to books and journal articles, are bills, statutes, and case law.
Bills are proposed legislation before they get approved as law.
Statutes are the laws as approved by a legislature (eg, federal Parliament or provincial assembly).
Case law or jurisprudence is the written decision of a judge or decision-maker made following the conclusion of case in court or before a tribunal.
For more on legal research, see the Law subject guide.