“Green OA” is often called "self-archiving" by publishers and refers to author-initiated open access. Authors can make their work open access by posting a version of their article in an open repository.

One advantage to choosing Green OA instead of Gold is that there is no cost associated with self-archiving and sharing your work, as there often is when making your research OA through a publisher. However, because the publisher holds the copyright on the published article, they control when, where, and what version can be posted. Contact your librarian or use Open Policy Finder to check journal-specific self-archiving policies.

Preprints and accepted manuscripts are the two most common article versions made available through Green OA. 

Preprints

A preprint is a manuscript that has not yet been submitted to a journal and may never be. These manuscripts are submitted to a disciplinary preprint server, where they are freely available and are open for comments. Preprints allow for rapid dissemination of new research and the feedback received can strengthen the manuscript. Many preprint servers allow authors to incorporate feedback into the manuscript, before it is submitted for publication in a journal. Readers need to be clear that because preprints do not undergo peer review, conclusions may have changed prior to publication. Preprints may also be called Submitted Version, Author's Original Manuscript (AOM), or Original manuscript.

Accepted Version

The accepted version is the final author-created version of a manuscript that has been accepted for publication and incorporates referee comments made during peer review. However, it may lack final copy-editing and does not incorporate the journal’s layout or pagination. It is also known as: Authors Accepted Manuscript (AAM), Authors accepted version, Final Author version, and Post-print. Publishers may allow these to be shared through a disciplinary repository or an institutional repository, but often after an embargo period has passed.

Open Peer Review is a general term used to describe any peer review model in which aspects of the peer review process are made publicly available, either before or after publication. Many publishers and journals use open peer review practices. Services such as PCI offer open peer review of preprints.

An institutional repository is a collection of research and creative works by people affiliated with that institution. Typically, such a repository may include faculty and researcher articles, accepted manuscripts, preprints, research data, presentations, reports, and working papers. In other words, anything that is appropriate for a researcher's CV and for which copyright and author agreements allow deposit of the content.  

Content archived in the University of Iowa's institutional repository, Iowa Research Online (IRO), is:

• discoverable by search engines such as Google and Google Scholar
• indexed and searchable in InfoHawk+, the University of Iowa Libraries' catalog
• hosted on a secure server and given a persistent URL to ensure permanent access
• registered with a digital object identifier (DOI) - for datasets, working papers, pre-prints, and accepted manuscripts
• openly accessible to researchers around the world who may have limited access to scholarly materials.

Disciplinary repositories are publicly available online archives that host and distribute preprints, accepted manuscripts, working papers, etc.