- closed = article only accessible with subscription to journal
- gold = open access article in full open access journal
- hybrid = open access article in subscription journal
- publisher = free access to article in subscription journal granted by publisher
- repository = free accessible version of subscription journal article in repository
open access = author retains copyright, published under creative commons license (free to use)Open access metadata from (peer) reviewed publications with a doi in unpaywall. Open access status is highly changeable. The data presented here has been harvested from unpaywall (7th of may 2020).