Resolve the DOI to its landing page, then query Crossref for the same DOI to retrieve deposited metadata, and compare the two records to fill gaps and flag any field that remains missing for manual verification. This two-source approach uses the publisher's landing page and the Crossref record to reconstruct the reference.
- Resolve the DOI. Enter the DOI in a DOI resolver. The DOI Handbook states that a DOI name resolves through the Handle System to current information supplied for the identified object, commonly a landing page maintained by the registrant. Note the publisher-deposited metadata visible on that page, such as title, authors, journal, year, volume, issue, and pages.
- Query Crossref for the DOI. Use the Crossref REST API to look up the DOI. According to Crossref's documentation, a DOI lookup returns the metadata deposited for that DOI, including structured fields for title, authors, journal, year, volume, issue, and pages.
- Compare the two records field by field. Check each element required for your citation style against both sources. Where the landing page provides a value that Crossref lacks, use the landing page value. Where Crossref provides a structured value that the landing page omits, use the Crossref value.
- Fill gaps from the landing page. If Crossref metadata is incomplete, return to the landing page to capture missing details. The landing page is the registrant's current information for the object, so it may include elements not present in the deposited metadata.
- Flag remaining missing fields for manual verification. If a required field is absent from both the landing page and the Crossref record, mark it as unresolved and verify it manually against the article PDF or another publisher source. Do not infer missing values from partial data.
- Format the reference. Use a style guide such as Citing Medicine for structured examples and rules for citing journal articles and other publication types.
This process works when the DOI resolves and at least one source provides partial metadata. If the DOI does not resolve, the approach does not apply; investigate the DOI's status separately.