How to Cite a Source You Can't Find or Access

If you need to cite a source you can't find, every major style has the same answer: cite the work where you actually read the material, and signal that the original passed through it. APA 7 calls this a secondary source citation and marks it with "as cited in" (Section 8.6). MLA 9 uses "qtd. in." Chicago uses "quoted in" and asks for both works in the note. This guide covers those three formats, plus the situations the phrase "can't find" actually hides: the paper behind a paywall, the webpage that no longer exists, the lecture that was never published, and the quote whose original source may never have existed at all.

One thing before the formats. All three manuals treat the secondary citation as a last resort, and graders read it the same way. Spend fifteen minutes trying to retrieve the original first. It is usually faster than you expect, and it upgrades your citation from "I trusted someone else's reading" to "I checked."

First, spend fifteen minutes trying to find it

Most "unfindable" sources are findable. Work through these in order and stop when one hits.

1. Paste the exact title into Google Scholar. Keep any quotation marks the citing text used. Scholar indexes preprints, institutional repositories, and author-hosted PDFs that ordinary search misses. For a paywalled result, click "All versions" under the listing; a free copy often sits in a university repository.
2. Decode the citation you do have. A reference like "Poetry 37 (1931): 269" tells you the journal, volume, year, and page. Your library's journal finder can take you straight to the archive that holds it. Librarians answer this exact question all day, often through a chat box on the library homepage.
3. Request it through interlibrary loan. Almost every academic library will get you a scanned chapter or article from another institution, usually within a few days, at no cost to you. Students routinely forget this service exists.
4. Check a preprint server. For science and social science papers, arXiv, bioRxiv, PsyArXiv, and SSRN carry near-final versions the authors posted themselves.
5. For a dead URL, check the Wayback Machine. Paste the address into web.archive.org. If the page was ever public, there is a good chance a dated snapshot survives. More on citing that below.
6. For an image, run a reverse image search. Google Images or a dedicated tool will often surface the original creator when all you have is a repost.
7. Email the author. Researchers are usually permitted to share their own accepted manuscripts and most are glad someone asked.

If all of that fails, you have a genuine secondary-source situation, and the styles have rules for it.

The APA 7 rule: "as cited in" (Section 8.6)

APA 7 covers secondary sources in Section 8.6 of the Publication Manual. The rule has two halves.

In the reference list, cite the work you read. The original never appears there, because your reader can't recover your reading of it; they can only recover the secondary source, the same way you did.

In the text, name both. Identify the original author, then add "as cited in" and the citation for the work you read. If you know the year of the original, include it.

Format:

(Original Author, Year, as cited in Author You Read, Year)

Suppose you read Agrios's 2005 textbook, which discusses findings Miller published in 1953, and Miller's paper is nowhere to be found. The in-text citations look like this:

Parenthetical: (Miller, 1953, as cited in Agrios, 2005) Narrative: Miller (1953, as cited in Agrios, 2005) found that...

And the reference list carries only the textbook:

Agrios, G. N. (2005). Plant pathology (5th ed.). Elsevier Academic Press.

When the original's year is unknown, drop it: (Allport, as cited in Nicholson, 2003). That example comes from APA's own style guidance, citing Allport's diary, which readers cannot consult, through Nicholson's 2003 work, which they can.

APA also says when a secondary citation is legitimate: the original is out of print, unavailable, or written in a language you don't read. "The library copy was checked out the night before the deadline" does not appear on that list, so expect an instructor to read a paper full of "as cited in" as a sign the research stopped early. One or two are fine.

If the secondary source itself is awkward to cite because it has no listed author or no date, that is a separate problem with its own rules; see our guides to citing a source with no author in APA 7 and citing a source with no date.

The MLA 9 rule: "qtd. in"

MLA 9 handles this with the abbreviation "qtd. in" (quoted in) inside the parenthetical citation. The Works Cited entry belongs to the indirect source, the work you actually consulted. The MLA Handbook's classic example quotes Alexander Pope through Damrosch's anthology:

According to Alexander Pope, "A little learning is a dang'rous thing" (qtd. in Damrosch 239).

Three details students miss:

• The original author's name can live in your prose (as above), in the parenthetical, or in an endnote. MLA leaves the placement to you.
• The Works Cited entry is for Damrosch. Pope gets no entry, because you never opened Pope.
• MLA says "qtd. in" is optional when your prose already makes clear the material is secondhand. If your sentence reads "In a letter reprinted by Damrosch, Pope wrote...", the parenthetical can be a bare (Damrosch 239).

Use "qtd. in" for quotations. If you are borrowing a paraphrased idea rather than quoted words, MLA's cleanest solution is the same as APA's spirit: make the chain of custody explicit in your prose and cite the source you read.

The Chicago rule: "quoted in"

The Chicago Manual of Style is the bluntest of the three. Its Q&A repeats the manual's position that citing through a secondary source "is generally to be discouraged, since authors are expected to have examined the works they cite." When the original genuinely cannot be consulted, Chicago's notes-and-bibliography style puts both works in the footnote, original first:

Louis Zukofsky, "Sincerity and Objectification," Poetry 37 (February 1931): 269, quoted in Bonnie Costello, Marianne Moore: Imaginary Possessions (Cambridge, MA: Harvard University Press, 1981), 78.

That example is the manual's own. Read its anatomy: a complete citation for Zukofsky's article, with the page the quotation sits on, then "quoted in," then a complete citation for Costello's book, with the page where you found it. Your bibliography lists Costello, the work you held in your hands.

This is more front-loaded work than APA or MLA asks for, because you need full publication details for an original you never saw. Take them from the secondary source's own note or bibliography, and copy them exactly; if Costello got Zukofsky's page number wrong, "quoted in" is precisely what protects you, since it tells the reader whose transcription you relied on.

When the source is gone: dead links and vanished pages

"I can't find it" sometimes means the source existed, you read it, and now the URL returns a 404. This is link rot, and APA has a concrete procedure for it.

First, look for an archived version. Paste the dead URL into the Wayback Machine at web.archive.org. Should a snapshot exist, cite the archived version and use the archive's own URL, the long one that starts with web.archive.org and embeds the capture date. Your reference keeps the original author, date, and title; only the URL changes. The capture-dated URL matters because the page may have been captured many times with different content, and your reader needs the version you read.

If no archive exists, APA's position is that the entry has to go. A reference list exists so readers can retrieve what you cited. A work nobody can retrieve fails that test, so APA guidance says to remove the entry and, where possible, cite another source that supports the same point. That feels harsh when the vanished page said exactly what you needed, but a citation your reader can chase to a 404 is worse than a rewritten sentence.

The durable fix is habit, not repair: archive pages yourself the day you cite them. The Wayback Machine's "Save Page Now" takes a few seconds and guarantees the snapshot you cite is the page you read.

When the source was never recoverable: personal communications

Some sources can't be found because they were never published anywhere. An email from your supervisor, an unrecorded lecture, a phone interview, a text message. APA 7 (Section 8.9) classifies these as personal communications, and the rule is the mirror image of everything above: they appear in the text only and never in the reference list, because no reader can retrieve them.

Parenthetical: (S. Brown, personal communication, July 22, 2026) Narrative: According to S. Brown (personal communication, July 22, 2026), ...

Give the communicator's initials and surname and the most exact date you can. Note the scope of the rule: a recorded lecture posted to a course site is a retrievable work with its own reference format, so the personal-communication rule applies only when nothing your reader could access exists. MLA and Chicago treat interviews and correspondence as citable works with their own formats rather than in-text-only mentions, so if you write in those styles, look up "personal interview" or "unpublished correspondence" in your manual instead of borrowing APA's device.

Special cases from real papers

The quote everyone repeats but nobody sources

You have a quotation that appears on dozens of websites, attributed to Einstein or Orwell or Angelou, and not one of them says where it comes from. Treat missing provenance as evidence: famous people attract misattributed quotes, and a line that exists only in quote collections frequently was never said by its supposed author. Quote Investigator and Wikiquote's sourced/unsourced split are the fastest checks. If you can trace the line to a checkable work, cite that work. If you can't, the defensible move is to cut the quote or attribute it honestly in prose ("a line often attributed to Einstein"), without a citation that would launder its credibility. "As cited in QuotesGarden" impresses no one grading a paper.

The claim you remember reading but can't re-find

Halfway through a draft you write "studies show..." and realize you can't remember which study. There is no citation format for a memory. Re-find the source with the retrieval steps above, or soften the sentence to what you can support, or cut it. Never cite a plausible-looking paper you didn't read on the hope it says what you remember; if a grader checks it and it doesn't, that looks far worse than a missing citation. A related trap is citing Wikipedia's article instead of the sources it lists. As one academic-integrity discussion put it, the complaint was never that Wikipedia exists; it was people citing the encyclopedia as if it were the research. Follow the article's footnotes to the underlying source, read it, then cite what you read.

The paper behind a paywall

"Can I cite a paper I don't have access to?" comes up constantly, and the honest answer is that citing means having read. An abstract is not the paper, and abstracts routinely oversimplify what a study found. Interlibrary loan, preprint servers, and an email to the author solve most paywalls within days. If the deadline is tonight and none of that lands in time, cite the accessible work that led you to the paper, with the secondary-source format above, and represent only what that work says.

The original is in a language you don't read

This is the one case APA explicitly blesses for secondary citation: a Japanese study you know through an English-language review can be cited as (Tanaka, 1998, as cited in Reviewer, 2010) with the review in your reference list. A translation you actually read is different: cite it directly, since published translations are ordinary retrievable works with their own reference formats.

Common mistakes and how to avoid them

• Citing the original as if you read it. The tempting shortcut is to copy the original's reference out of the secondary source's bibliography and cite it directly. If the secondary author misquoted or misread the original, you now repeat their error under your own name, and a reader who checks will find your account doesn't match the source. The "as cited in" chain exists to keep responsibility where it belongs.
• Putting both works in the APA reference list. Only the source you read gets an entry. A reference for a work you never saw invites your reader to a source you can't vouch for. Chicago is the exception, and even there the original lives in the note, with only the consulted work in the bibliography.
• Writing "qtd. in" in the Works Cited. The abbreviation belongs in the in-text parenthetical only. The Works Cited entry for the indirect source is a normal entry.
• Mixing the direction. Students sometimes write (Agrios, 2005, as cited in Miller, 1953), reversing the chain. The pattern is always original first, then "as cited in," then the work you read. The work after "as cited in" is the one in your reference list.
• Leaving a dead URL in the list. If you know the link is dead, your reader will too. Swap in the archived URL or replace the source before you submit. Checking every link is a five-minute pass; it pairs well with the full audit in our guide to fixing citation errors.

Quick-reference table