19 October 2026 · By Thesisroom

How to Verify References: Six Checks for Any Citation

A per-reference method to verify any citation: resolve the DOI, compare the Crossref record, open the publisher page, use a library catalogue and check Retraction Watch.

How to verify references: take one reference at a time and confirm that its DOI resolves, that the Crossref record matches every field, and that the publisher's page shows the same work. For books and works without a DOI, use a library catalogue. Then check Retraction Watch, and read the passage you rely on.

This guide is the per-reference method. Each check below says what to open, what to compare and what each result means, with a real reference worked through from start to finish. Auditing a whole reference list before a viva or defense is a different job, covered in our guide to thesis defense reference list checking.

Before you start: set up a verification log

Keep a short log so you check each reference once and can show your work later. A spreadsheet with one row per reference is enough.

Reference	DOI opens it	Crossref match	Publisher page	Retraction status	Passage (page)	Result
(Author, Year)	Yes / No / None	Yes / Differs	Seen	None / Notice	p. (n)	Keep / Fix / Remove

Fill in the last column only after the other six. That order stops you keeping a reference because it "looks fine".

Check 1: Resolve the DOI at doi.org

Put https://doi.org/ in front of the DOI and open it. If the page that opens shows the same title and authors as your reference, the first check passes.

A DOI is a Digital Object Identifier: a prefix and a suffix separated by a forward slash, such as 10.1000/182, according to the DOI Foundation's explanation of what a DOI is. The DOI system looks up that string and redirects you to the object it points to. Its metadata can be updated without changing the DOI itself, and the DOI Foundation says it complies with ISO 26324.

Copy and paste the DOI rather than retyping it. APA Style's guidance on DOIs gives the same advice, to avoid transcription errors. If you are unsure what the parts of a DOI mean, our guide to what a DOI is in a reference explains them.

The result is one of three. Each points to a different next step.

It opens the cited work. Move to check 2.
It opens a different work. The DOI is wrong, or the reference was assembled from parts of different records. Search for the cited title in check 2 before deciding which.
It fails to resolve. Recheck for a copying error first. If it still fails, search by title and author in check 2.

Check 2: Compare the record in Crossref

Crossref is one of the DOI registration agencies named by the DOI Foundation, and its members deposit metadata for their content with it. Search the title in Crossref Metadata Search, or open the record directly in your browser. Crossref is not the only agency: DataCite, also on that list, provides DOIs for research data, so check which agency registered a dataset's DOI.

For a direct lookup, type https://api.crossref.org/works/ followed by the DOI. The Crossref REST API documentation says no sign-up is required, and the record comes back as JSON with bibliographic data and post-publication updates.

Compare every field, not just the title. A title match alone does not show that the authors, year or journal are right.

All authors, spelled the same and in the same order
The full title
The journal or book title
The year
Volume, issue and pages, or the article number

If one field differs, correct your reference from the record. If several fields differ, or the record belongs to a different work, treat the reference as unverified until check 3 or 4 settles it.

Worked example: one real reference, checked

Take this reference, which we verified while writing this guide. It is an open-access paper, so you can repeat each step yourself.

Walters, W. H., & Wilder, E. I. (2023). Fabrication and errors in the bibliographic citations generated by ChatGPT. Scientific Reports, 13(1), Article 14045. https://doi.org/10.1038/s41598-023-41032-5

The DOI redirects to the article page on nature.com. The Crossref record for this DOI gives the same title, the authors William H. Walters and Esther Isabelle Wilder, Scientific Reports, volume 13, issue 1, article number 14045, published online on 7 September 2023.

Every field matches, so checks 1 and 2 pass. The Crossref record has no update-to field, so no correction or retraction is registered there. Checks 3 and 5 are still needed before this row is complete.

Check 3: Open the publisher's page

The publisher's page is where the published article lives, so open it even when Crossref matches. You are looking for three things: the same details, the full text or abstract, and any notice attached to the article.

Look near the title and in the article information for corrections, expressions of concern or retraction notices. Crossref members can also place a Crossmark button on their content. Crossref's Crossmark documentation says it gives readers the current status of an item, including corrections, retractions or updates.

The same page adds that the presence of Crossmark "is not a guarantee" of a publisher's practices. So treat a clean Crossmark as one signal, not proof, and still run check 5.

Check 4: Use a library catalogue or subject database when there is no DOI

Books, book chapters, older papers and reports may have no DOI, so search for them by title and author instead. Our guides on finding the DOI for an old paper and citing a paper with no DOI cover those cases in detail.

Source type	Where to look	What it says about itself
Books and chapters	WorldCat, then your own library catalogue	"The world's largest library catalog"
Biomedical and life science papers	PubMed	More than 40 million citations for biomedical literature
Papers in any field	OpenAlex	A free and open catalogue of the world's research

For a book chapter, confirm that the book itself exists before you look for the chapter inside it. In Walters and Wilder's study, 70 percent of the book chapters ChatGPT cited were fabricated, for both GPT-3.5 and GPT-4. The parent book itself was invented in 57 percent of the fabricated GPT-3.5 chapters and 19 percent of the GPT-4 ones.

Check 5: Search the Retraction Watch Database

A real, correctly cited paper can still have been retracted, so check its status. Search the Retraction Watch Database by title keywords, author, or the DOI of the original paper. Its user guide gives the database address and advises searching with keywords rather than full titles. Results also include corrections and expressions of concern, so read what each entry is.

Crossref acquired the Retraction Watch database in September 2023, according to Crossref's Retraction Watch page. Retractions now appear in the update-to field of the Crossref record from check 2, marked by source as publisher or Retraction Watch. If you find one, our guide on what to do if a paper you cited is retracted walks through the decisions.

Check 6: Read the passage you rely on

A reference can pass every check above and still not support your sentence. Open the full text, find the passage behind your claim and write its page number in your log.

If the abstract says one thing and your sentence says more, the sentence is the problem. Narrow the claim to what the source says, or find a source that says the rest.

How to verify references from the results

Once the six checks are done, every reference falls into one of five outcomes. The table gives the action for each.

What you found	What it means	Action
DOI, record, publisher page and passage all match; no notices	Verified	Keep it
Record found, one or more fields differ	Miscited	Correct each field from the publisher's record
No DOI, but a catalogue or database record matches	Verified without a DOI	Keep it, formatted as your style requires
Retraction or expression of concern found	Status changed	Read the notice, then decide whether and how to keep it
No record anywhere after checks 1 to 4 and the journal's own issue listing	Unverified, possibly hallucinated	Remove it, or keep searching only if you hold a copy of the work

A reference you cannot find in registries is not automatically fake. A local report or an old conference paper may simply not be indexed. If you hold a copy, you have your proof; if no one can produce one, remove it.

How to check references in a paper you are reading

Use the same six checks, but start with the references that carry the claims you plan to borrow. If you cite a paper for a finding, check the source it cites for that finding before you repeat it.

This matters most when you take a reference from another paper's list instead of reading it yourself. Run checks 1, 2 and 6 on it as if it were your own.

How to check if a citation in your thesis is real

For your own thesis, run all six checks on every reference that came from a chatbot, a summary or another author's list. For references you found and read yourself, checks 1, 2 and 5 confirm the details and status.

When you want to check your whole reference list rather than one entry, the order and the extra passes change. That full audit is in our thesis defense reference list checking guide.

What Thesisroom does with this

Thesisroom's Citation Check looks each reference up in eight registries: Crossref, OpenAlex, Semantic Scholar, PubMed, Retraction Watch, DOAJ, CORE and Unpaywall. CORE and Unpaywall add context but never verify a source on their own. It shows which references it could verify, which are retracted, and which need checking by hand, with the record it compared against.

The free citation checker takes pasted references with no account needed, using a smaller set of registries. Neither one reads the passage for you: check 6 stays with you.

Frequently asked questions

What is the quickest way to verify one reference?

Paste its DOI after https://doi.org/ and compare the page that opens with your reference. Then search the title in Crossref Metadata Search and the Retraction Watch Database. If there is no DOI, search the title in WorldCat or a subject database.

How can I tell if a chatbot gave me a fake citation?

You cannot tell by looking. Run checks 1, 2 and 4: resolve the DOI, search Crossref by title, and search a catalogue. If nothing matches and the journal's own issue listing does not show it, treat it as fabricated and remove it.

Does a DOI that resolves prove the citation is correct?

No. It proves the DOI exists. The page it opens must show the same title, authors, journal and year as your reference. A DOI copied onto the wrong reference will resolve perfectly and still be wrong.

Is Crossref free to use for checking references?

Yes for the REST API: Crossref's documentation says no sign-up is required to use it. You can open a record in a browser by typing https://api.crossref.org/works/ followed by the DOI.

How do I check if a paper has been retracted?

Search the Retraction Watch Database by title keywords, author or DOI, and check the publisher's page for a notice. The Crossref record for the DOI also lists retractions in its update-to field. Results can include corrections and expressions of concern, so read each one.

What if I cannot verify a reference I really did read?

Keep searching in a library catalogue and the publisher's site, and look at your own copy for an identifier. If it is a report or local document, cite it in the format your style guide gives for that type of source.

Sources

How this guide was made: Thesisroom drafted this guide with the help of AI writing tools, then checked every fact, figure and source by hand against the references linked above.