Thomson Reuters
Find Law: u.s. Constitution: Article I
Complete text of Article I, sections 1-10, of the U.S. Constitution, establishing the Legislative Branch of the Federal government.
University of Groningen
American History: Outlines: The Legislative Branch: The Reach of Congress
This well-written and well-organized site from The Legislative Branch provides a thorough overview of congressional powers, inherent checks and balances, as well as links to related information.