Query the paper's DOI in Unpaywall to see the open-access locations recorded for that article, then check repository copies through CORE if Unpaywall lists none, and confirm the copy's version matches the version you cited before relying on it.
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. That record tells you where a legal open copy has been recorded, so start there rather than with a general web search.
- Look up the DOI in Unpaywall and read the recorded open-access locations. Expected result: a list of locations with host type and version, or no listed location for that DOI.
- If locations are listed, open the selected best location first and note its version and license. Decision point: if the version matches the version cited in your analysis, use it; if it differs, continue to the next step.
- If Unpaywall lists no open-access location, search CORE for the paper. CORE aggregates open-access research outputs and offers discovery services and tools for finding repository copies of scholarly work. Expected result: repository copies you can inspect for version.
- Compare the copy's version against the cited version before quoting or relying on it. A repository copy can be a different version from the one cited, so the version field determines whether the text supports your claim.
If the cited paper appears in an open-access journal, DOAJ provides searchable article and journal records for open-access journals that meet its inclusion criteria, which can help you confirm the article's open-access status.
When neither Unpaywall nor CORE surfaces a usable copy, treat the full text as unresolved and record that status in your source set instead of substituting an unverified copy.