Set up a lawful open-copy check by looking up the paper's DOI in open-access location services, recording the host type, version, and license for any copy you find, and documenting the result—including when no lawful copy exists—before you cite the paper. This turns "paywalled" into a recorded access decision instead of an assumption that the paper is unavailable.
Run the check in order
- Start with the DOI. Take the DOI from the publisher page or the paper's record and use it as the lookup key. Unpaywall records describe open-access locations associated with a DOI, including host type, version, license information when available, and a selected best open-access location. Record the DOI you searched so the check can be repeated.
- Read the location record, not just the presence of a link. For each open-access location, note the host type (for example, a repository or publisher site), the version, and the license when the record provides one. These fields tell you what kind of copy you are looking at and what its license permits.
- Cross-check repository coverage. CORE aggregates open-access research outputs and offers discovery services and tools for finding repository copies of scholarly work. If the first lookup returns no location, search CORE for the title or DOI to see whether a repository copy is indexed.
- Check journal-level open access. DOAJ provides searchable article and journal records for open-access journals that meet its inclusion criteria. Use it to confirm whether the journal itself is listed as open access, which helps explain why a copy may or may not appear elsewhere.
- Record the outcome. Write one line in your notes: the DOI, the services checked, any host type, version, and license found, and the date. If no lawful copy appears, record that result explicitly rather than leaving the access status blank.
What each outcome means for your citation
- A copy with a stated license: note the license alongside the version, since the version and license together describe what you found.
- A copy with no license information in the record: record the host type and version and treat the license as unstated in your notes.
- No copy found: record the services you checked and the date. This documents that you looked, and it gives you a clear basis for deciding how to access the paper next, such as through your library.
Keep the record with your reference notes so that the access decision is visible when you or a co-author revisit the citation before submission.