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Open Access

Introduction to the concept of Open Access research and how to find it.

Preprint vs. Postprint

When using Green Open Access literature, the distinction between a preprint and a postprint is very important. While the definitions can vary, "preprint" refers to a copy of the article before the peer review process and "postprint" refers to a version of the article that has been peer reviewed but is not the final published version. A preprint article may be significantly different from the final version, depending on what (if anything) was changed during the peer review process. A postprint, by contrast, should contain the same content as the final published version, though the appearance may be different. 

Always ask your instructor whether preprint, or even postprint, versions of articles are acceptable for your assignments. If they are not allowed, the library can try to obtain copies of the final articles for you if they are not in our collections. 

Finding Green OA in Repositories

Repositories are online collections of Green Open Access literature. 

They come in two types:

  • Subject repositories collect content based on a broad subject area. Popular examples include arXiv for physics research operated by Cornell Libraries and PubMed for medical research funded by the US National Library for Medicine
  • Institutional repositories collect content created by the faculty, staff, and students of that college or university. An example of this type is Ohio State University's Knowledge Bank 

Below are some popular depositories.

Google Scholar will also find items held in most depositories.

Other Ways to Find Green OA

Scholars may post versions of their published papers on their faculty webpages or through scholarly social networks such as Always check to see if they label what version of the article it is--if they do not provide that information, it is safest to presume it is the preprint version.