http://www.law.cornell.edu/ucc/ucc.table.html
This site contains the full text of articles one to nine of the Uniform Commercial Code (UCC). The states, not the federal government, are the primary source of law on commercial transactions in the US, but in all 50 states and the District of Columbia at least some of that commercial law is based on the Uniform Commercial Code. The version appearing in this site is the most recent version, and most of its provisions are in effect in most of the US states.