When Lean Library extension identifies a DOI on a page, see here for how we do that, we will use this DOI to look for a legal Open Access copy of the article.
How does the extension find Open Access versions of articles via Unpaywall?
On the occasion when you cannot access an article via your library holdings, we'll look for an Open Access version via Unpaywall and Core.ac.uk.
With Unpaywall, our pop-ups specify the type of Open Access version in plain text. For example, the below Open Access version provided by our extension via Unpaywall is the "Published Version - Unpaywall":
The possible versions from Unpaywall are "Submitted Version", "Accepted Version" and "Published Version". This version classification is only available for content sourced via Unpaywall.
Below is an explanation of each version:
Submitted Version is not yet peer-reviewed.
Accepted Version is peer-reviewed, but lacks publisher-specific formatting.
Published Version is the version of record.