In recent years, finding cases and other legal materials no longer requires a trip to a library. The following are links to materials useful for constitutional interpretation.
United States Supreme Court website: https://www.supremecourt.gov.
Legal Information Institute: http://www.law.cornell.edu.
OYEZ Project, U.S. Supreme Court Multimedia: http://www.oyez.org.
If you are interested in ordering a copy of American Constitutional Interpretation, please visit the publisher's website.