PaperCitation

How the checks work

We compare each reference you paste with the published record in scholarly databases, and show you the record so you can judge for yourself.

Step by step

  1. Split and clean. We split your list into separate references and remove numbering, bullets and stray formatting.
  2. Find identifiers. We look for a DOI, ISBN, PubMed ID, arXiv ID or URL in each reference.
  3. Look it up. A reference with a DOI is looked up directly. Without one, we search by title and compare the authors, year and journal.
  4. Read messy references. If a reference is too irregular to read with simple rules, an AI model (Anthropic's Claude Haiku) splits it into fields such as author, title and year. Those fields are only used as search terms. The AI never decides the verdict and never fills in missing details.
  5. Compare. We compare the title, author surnames, year and journal with the record we found. Small typos in titles are tolerated, and a one-year difference is allowed, because print and online publication dates often differ. A title match alone isn't enough: the author or year you wrote must agree with the record too, because many works share a title.
  6. Check for retractions. We check whether the matched paper has been retracted, using retraction information published through Crossref, which includes Retraction Watch data.
  7. Format. We build a corrected citation from the database record, in the style you choose. Only details that come from the database appear in it.

Where the data comes from

What the verdicts mean

Verified

We found a record that matches your reference on the key details. We show you the record and a link to it.

Mismatch

We found the work, but some details differ, such as the year, an author or the title. We show exactly what's different so you can fix it.

Couldn't verify

We couldn't find a matching record. We tell you the most likely reason: there was no DOI and no title match, the source looks like a book, thesis or report, the title isn't in English, or a database was temporarily unavailable.

"Couldn't verify" doesn't mean the source is made up. Plenty of real sources aren't in these databases. Check it in your library's catalog or with a librarian.

Fix formatting

Shown with a verdict when we found your source, but what you wrote isn't a complete citation yet, for example a list of words with no punctuation, or a reference missing the authors, year or journal. Use the corrected citation we provide. We check that the main parts are there; we don't grade every rule of a style guide.

A title on its own

A title by itself can't be checked, because it doesn't say which work you mean. We tell you to add the author and year, and suggest up to three works with that title, each with a ready citation. Suggestions aren't a check: make sure one is the source you actually used.

Retracted

A warning shown on top of any verdict when the matched paper has been formally retracted, withdrawn or removed, or has an expression of concern from its publisher. Retracted papers generally shouldn't be cited as evidence, except when you're writing about the retraction itself.

Corrected citations

Corrected citations are built by software from the database record, using the official style definitions from the Citation Style Language project, in APA 7, MLA 9, Chicago 18 (author-date), Harvard (Cite Them Right, 12th edition as defined in CSL; Harvard has no single official version, so follow your school's guide if it differs) and IEEE. Only details that come from the database appear in them, so if the database is missing something (for example a page range or a book's publisher), the citation will be missing it too. Databases also store titles the way publishers send them, so you may need to adjust capitalization, for example to sentence case in APA.

Limits

If we got something wrong, please tell us. Reports help us improve matching.

Last reviewed October 10, 2026