The Federal court system is composed of 94 district courts along with other trial courts, 12 courts of appeal, and a single supreme court. The U.S. Supreme Court can overturn statutes determined to conflict with the Constitution. When looking for U.S. Supreme Court cases bear in mind that slip opinions will often appear online within minutes. The United States Reports are the official reporter of the U.S. Supreme Court, but its publication is very delayed, so commercial titles may be more useful.
When citing cases, ensure you follow standard citation practice, such as that outlined in The Bluebook.
Case citations are normally formatted: Party Names, Vol# Abbreviation Page# (jurisdiction. year).