Determining if a material is copyrighted can be complicated.  The tools available at the links below can be used as a guide.

• Copyright Term and the Public Domain in the United States 
  Cornell University houses this document to help determine if works are under copyright.
• Taking the Mystery Out Of Copyright 
  Presented by the Library of Congress, this is a series of cartoons suitable to use with students when teaching copyright concepts.
• Fair Use Slider 
  This tool can be used to determine if a material is copyrighted.
• Public Domain Sherpa 
  This tool can be used to check if a material is in the public domain and not protected under copyright.
• Public Domain and Creative Commons Guide 
  This tool discusses public domain as well as Creative Commons. Creative Commons is an alternative to copyright that allows a content creator to apply several different permissions to a material.
• Foreign Copyright and Public Domain Information 
  The Cornell Copyright Information Center has produced this guide to public domain and materials published outside the United States.
• Stanford University Libraries Public Domain Guide 
  This guide to public domain includes a good overview of the concept of public domain and how public domain applies to a variety of material formats.
• Creative Commons Licenses 
  An alternative to copyright that provides tiered levels of permissions for content creators. Creative Commons licenses can grant substantial rights to those wishing to use licensed materials.