Public domain materials are also free to use and reuse because they are not registered as copyrighted, or their copyrights have expired. Anyone can use a public domain work without obtaining permission.

• Check out Stanford Libraries’ information about public domain.
• For an overview of public domain, see this FAQ from TeachingCopyright.org.
• Sometimes it can be tricky determining if something is in the public domain yet. Copyright.gov provides information on the duration of copyright.

The following links are some good resources for finding public domain works:

• Project Gutenberg
  Project Gutenberg is the largest collection of public domain ebooks on the Internet.

• LibriVox
  Public domain audiobooks read by volunteers across the world.

• Smithsonian Institution Public Domain Images
  The Smithsonian's flickr account of images in the public domain that they have digitized from their collections.

• Internet Archive
  Internet Archive is a digital library of Internet sites and other cultural artifacts in digital form. Use this link to search for items under public domain.

Many authors of online resources are adapting to the new way we use and reuse material on the Internet by turning to Creative Commons licenses. You've probably seen the logos below on various scholarly and popular websites (listed in order from most to least permissive). These logos inform you what you are permitted to do with the work.

	CC BY: Credit must be given to the creator
	CC BY-SA: Credit must be given to the creator and adaptation must be shared under the same terms
	CC BY-NC: Credit must be given to the creator and only noncommercial uses of the work are permitted
	CC BY-NC-SA: Credit must be given to the creator, only noncommercial uses of the work are permitted, and adaptations must be shared under the same terms
	CC BY-ND: Credit must be given to the creator and no derivatives or adaptations of the work are permitted
	CC BY-NC-ND: Credit must be given to the creator, only noncommercial uses of the work are permitted, and no derivatives or adaptations of the work are permitted

Open Access (OA) is the “free, immediate, online availability of research articles combined with the rights to use these articles fully in the digital environment” (SPARC).

There are different types of open access journals with varying publishing models you should watch out for:

• Gold - Journals fully accessible under a creative commons license or similar with an article processing cost (APC)
• Hybrid - A subscription journal in which the publisher allows authors to pay an APC to make their individual articles open access
• Diamond/Platinum - An open access journal that does not charge APC
• Bronze - Open access journals that are free to read online, but not available for reuse
• Green - Self-archived pre- or post-print articles in repositories

To find open access resources, check out the list of OA databases in this guide. If you have a resource that you want to share with someone who doesn't have institutional access, here are a few databases you can use to see if an open access version of the resource is available online:

• OAIster
• Open Access Button
• Directory of Open Access Journals