Law review articles are scholarly articles written by legal scholars and law school students and contain many footnotes, which is a quick way to find primary documents.
HeinOnline is an image-based legal research database with over 50 million pages of legal information in fully-searchable PDF format, comprising over 30 separate collections including Law Journal Library, Legal Classics, U.S. Supreme Court Library, U.S. Federal Legislative History Library, U.S. Congressional Documents, Treaties and Agreements Library and many others. Additional titles and years are added regularly.
The scholarly articles in these databases will provide footnotes, often to primary sources.