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How to Cite a Secondary Source (As Cited In)

A secondary-source citation says two things at once: this idea belongs to one author, and I read it in another author's work. APA 7 writes as cited in and lists only the work you read. MLA 9 writes qtd. in and lists only the work you read. Chicago 18 writes quoted in and lists both. All three manuals say the same thing first: get the original if you can. This guide covers the citation mechanics, not the research-methods meaning of "secondary source," and it is not the reprint and translation workflow.

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Quick Answer: cite a secondary source

Name the original author in your sentence or parenthetical, then point to the work you actually read. In APA 7 the phrase is as cited in, and only the work you read goes in the reference list. In MLA 9 the phrase is qtd. in, and only the work you read goes in the works-cited list. In Chicago 18 the phrase is quoted in, and the note or reference entry carries both works. Never list a work you have not opened as if you had.

Templates: the original is Brandt, the work you read is Okafor and Lindqvist

APA 7 parenthetical:

(Brandt, 2004, as cited in Okafor & Lindqvist, 2021)

APA 7 narrative:

Brandt (2004, as cited in Okafor & Lindqvist, 2021) argued that …

APA 7 reference list:

Only Okafor & Lindqvist (2021). Brandt does not get an entry.

MLA 9 in-text:

Brandt called rehearsal "re-creation, not storage" (qtd. in Okafor and Lindqvist 143).

MLA 9 works cited:

Only Okafor and Lindqvist. Brandt does not get an entry.

Chicago 18 note:

1. Rolf Brandt, "Rehearsal Effects in Serial Recall," Journal of Memory Studies 12, no. 3 (2004): 211, quoted in Chidi Okafor and Maja Lindqvist, The Science of Remembering (Meridian Academic Press, 2021), 143.

Chicago 18 author-date:

(Brandt 2004, 211) in the text; the Brandt reference entry ends with "Quoted in Okafor and Lindqvist 2021, 143." and Okafor and Lindqvist get their own entry.

What "secondary source" means in a citation

In citation manuals the phrase is about access, not about the kind of document. The primary source is the work whose idea, data, or words you are using. The secondary source is the work in which you encountered it. A 2021 textbook summarising a 2004 experiment is the secondary source; the 2004 article is the primary source. That is a different distinction from the historian's primary-versus-secondary split, where a diary is primary and a monograph is secondary. This guide uses the citation meaning throughout.

The mechanics exist because the alternative is dishonest. If you cite Brandt (2004) directly after reading only Okafor and Lindqvist's summary, your reader assumes you checked Brandt, and any error in the summary becomes your error. If you cite only Okafor and Lindqvist, you strip Brandt of credit for the idea. The as cited in chain is the only form that tells the truth about both.

Find the original first

Every manual leads with the same instruction. APA's secondary sources page says to use them sparingly, for instance when the original is out of print, unavailable, or in a language you do not read. The MLA Handbook's section on indirect sources opens by telling you to take material from the original whenever you can. The Chicago paragraph on citations taken from secondary sources calls the practice "generally to be discouraged." Instructors read a page full of as cited in as a sign that you never left the textbook.

  1. Copy the full reference of the original from the secondary source's reference list or note. That entry is the reason the secondary source cited it.
  2. If the entry has a DOI, paste it into the DOI citation generator or a browser. A DOI resolves to the publisher's page; see how to use DOIs if it does not.
  3. Search the title in your library catalogue and Google Scholar. Most twentieth-century journal articles are digitised, and many pre-1923 books are free.
  4. Request an interlibrary loan if the item is not in your collection. Turnaround is usually days, not weeks.
  5. Once you have the original, read the passage in context and cite it directly. The chain disappears and the secondary source only stays in your list if you also use it for something else.
  6. If all of that fails, or the original is in a language you cannot read, cite it as a secondary source using the forms below.
When a secondary-source citation is defensible.
SituationCite the original directly?Use the secondary form?
The original is a journal article with a DOIYes, alwaysNo
The original is out of print and not in any library you can reachNot possibleYes
The original is in a language you do not readNot without a translationYes, or cite a published translation directly
The original is an unpublished letter, diary, or interview quoted in a biographyOnly if the archive is open to youYes
You want to discuss how the secondary author interpreted the originalCite both, each for its own wordsNot needed; you are citing the secondary author's own claim
The secondary source is a lecture slide or study guideYes, find the source it summarisesAvoid

APA 7: "as cited in"

APA 7 §8.6 and the APA Style secondary sources page put the whole chain inside the in-text citation and keep the reference list honest: only works you consulted appear in it. The primary source is named first, then the phrase as cited in, then the secondary source in ordinary author–date form. If you know the primary source's year, include it after the primary author's name. If you do not, leave it out; do not write n.d., which would claim you checked and found no date.

APA Style, secondary sources

In the text, identify the primary source and write "as cited in" the secondary source that you used.

APA 7 official in-text patterns

Parenthetical, primary year known:

(Rabbitt, 1982, as cited in Lyon et al., 2014)

Narrative, primary year unknown:

Allport's diary (as cited in Nicholson, 2003) …

Reference list:

Lyon et al. (2014) and Nicholson (2003) are listed. Rabbitt (1982) and Allport are not.

Worked example: a 2004 article you read about in a 2021 book

Okafor and Lindqvist's book summarises an experiment by Brandt. You could not obtain Brandt's article. Every in-text form below points the reader to the book, and the book is the only entry the reference list gains.

APA 7, full worked example

Reference list (the secondary source only):

Okafor, C., & Lindqvist, M. (2021). The science of remembering: How rehearsal shapes recall. Meridian Academic Press.

Parenthetical, paraphrase:

Rehearsal changes the memory it repeats (Brandt, 2004, as cited in Okafor & Lindqvist, 2021).

Narrative, paraphrase:

Brandt (2004, as cited in Okafor & Lindqvist, 2021) found that rehearsal changes the memory it repeats.

Direct quotation (page of the secondary source):

Brandt described rehearsal as "re-creation, not storage" (as cited in Okafor & Lindqvist, 2021, p. 143).

Primary year unknown:

(Brandt, as cited in Okafor & Lindqvist, 2021)

The page number belongs to the secondary source, because that is the page your reader can check. Do not copy Brandt's original page numbers from Okafor and Lindqvist's citation into your parenthetical; you have not seen those pages. Use the APA in-text citation generator for the outer author–date pair and type the as cited in phrase by hand.

APA variations

  • Ampersand versus and. Inside parentheses the secondary authors are joined with &; in a narrative sentence, with and. The rule is the same as for any APA citation; see how to cite multiple authors.
  • Three or more secondary authors. Shorten the secondary source with et al. exactly as you would normally: (Brandt, 2004, as cited in Reyes et al., 2019).
  • The primary source is a personal communication. A letter or interview quoted in a published work is still cited with as cited in, because your reader can find the published work. The personal communications rule applies only to communications you received.
  • Two different secondary sources report the same primary work. Cite each chain separately; do not merge them into one parenthetical.
  • You later obtain the original. Replace the chain with a direct citation and add the original to the reference list. Remove the secondary source unless you cite it for its own claims.

MLA 9: "qtd. in"

MLA 9 handles indirect sources with the abbreviation qtd. in ("quoted in") placed before the source you consulted inside the parenthetical. MLA uses the same abbreviation whether you are quoting the original's words or paraphrasing them; the abbreviation signals that the material came to you through an intermediary. The works-cited list follows the same principle as APA: it contains only the work you read. The MLA Style Center is the official home of the rule; the Handbook's own example cites a remark by Samuel Johnson through Boswell's Life of Johnson, with only Boswell in the works-cited list.

MLA 9, full worked example

Works cited (the secondary source only):

Okafor, Chidi, and Maja Lindqvist. The Science of Remembering: How Rehearsal Shapes Recall. Meridian Academic Press, 2021.

In-text, quotation, original author named in the sentence:

Brandt described rehearsal as "re-creation, not storage" (qtd. in Okafor and Lindqvist 143).

In-text, paraphrase, original author named in the sentence:

Brandt's 2004 experiment showed that rehearsal alters the memory it repeats (qtd. in Okafor and Lindqvist 143).

In-text, three or more secondary authors:

(qtd. in Reyes et al. 27)

Put the original author's name in your prose, as the Handbook's Johnson example does. The parenthetical then only has to do one job: tell the reader where to look. A reader who sees (qtd. in Okafor and Lindqvist 143) after a sentence that already says "Brandt" has both halves of the chain. There is no comma between the secondary authors and the page number, because MLA never puts one before a page number; the MLA in-text guide covers that spacing.

What MLA does not want

  • A works-cited entry for Brandt when you never opened Brandt. MLA's list is a record of what you consulted.
  • "Cited in" or "as cited in." Those are APA phrases; MLA's abbreviation is qtd. in, with a period after qtd.
  • Brandt's original page number. The page is Okafor and Lindqvist's, because that is where the reader will find the passage.
  • A bare (Okafor and Lindqvist 143) with no qtd. in after a sentence attributing the idea to Brandt. That reads as if Okafor and Lindqvist made the claim themselves.
  • qtd. in when you did read the original. If you are quoting Brandt from Brandt, cite Brandt.

Chicago 18: "quoted in"

Chicago is the only one of the three that records both works in the note and the bibliography. The paragraph on citations taken from secondary sources (§14.160 in CMOS 18; §14.260 in CMOS 17) discourages the practice, then says that if the original is unavailable, both the original and the secondary source must be listed. The link word is quoted in, lowercase in a note and capitalised as Quoted in when it opens a new sentence in a bibliography entry. The official Notes and Bibliography citation guide sets the format for each half.

Notes-Bibliography

Chicago 18 notes-bibliography, full worked example

First note:

1. Rolf Brandt, "Rehearsal Effects in Serial Recall," Journal of Memory Studies 12, no. 3 (2004): 211, quoted in Chidi Okafor and Maja Lindqvist, The Science of Remembering: How Rehearsal Shapes Recall (Meridian Academic Press, 2021), 143.

Shortened note:

2. Brandt, "Rehearsal Effects," 211, quoted in Okafor and Lindqvist, Science of Remembering, 143.

Bibliography (original, carrying the chain):

Brandt, Rolf. "Rehearsal Effects in Serial Recall." Journal of Memory Studies 12, no. 3 (2004): 211. Quoted in Chidi Okafor and Maja Lindqvist, The Science of Remembering: How Rehearsal Shapes Recall (Meridian Academic Press, 2021), 143.

Bibliography (secondary source, its own entry):

Okafor, Chidi, and Maja Lindqvist. The Science of Remembering: How Rehearsal Shapes Recall. Meridian Academic Press, 2021.

Two details follow the manual's own Zukofsky-and-Costello example. The original's page reference is the page where the quoted passage sits in the original, as reported by the secondary source, not the article's full page range. And the bibliography entry for the original ends with a full sentence beginning Quoted in, which is why the secondary source's details appear there in note form (first name first, parentheses around the publisher) rather than bibliography form. CMOS 18 no longer requires a place of publication for books published after 1900, so none appears above. Build the outer note with the Chicago footnote generator and add the quoted in clause by hand.

Author-Date

In author-date the chain moves into the reference list. The original gets an entry that ends with Quoted in plus the secondary source's author–date label and page; the secondary source gets a normal entry of its own. The text citation then cites the original, and a reader who follows it to the list finds the chain there. The Author-Date citation guide sets the format of both entries.

Chicago 18 author-date, full worked example

Reference list (original, carrying the chain):

Brandt, Rolf. 2004. "Rehearsal Effects in Serial Recall." Journal of Memory Studies 12 (3): 211. Quoted in Okafor and Lindqvist 2021, 143.

Reference list (secondary source):

Okafor, Chidi, and Maja Lindqvist. 2021. The Science of Remembering: How Rehearsal Shapes Recall. Meridian Academic Press.

In-text:

(Brandt 2004, 211)

If you want the chain visible in the sentence:

Brandt (2004, 211), as quoted by Okafor and Lindqvist (2021, 143), found that …

Do not turn the author-date reference into (Brandt 2004, as cited in Okafor and Lindqvist 2021). That is APA's phrasing dropped into Chicago punctuation, and a Chicago reader will look for the Quoted in sentence in the list and not find it.

Three styles side by side

APA 7

Phrase:

as cited in

In the list:

Secondary source only

Primary year:

Include it if known; omit if not

Page:

Secondary source's page, for quotations

MLA 9

Phrase:

qtd. in

In the list:

Secondary source only

Primary year:

Not part of the citation; mention it in prose if useful

Page:

Secondary source's page, no comma before it

Chicago 18

Phrase:

quoted in / Quoted in

In the list:

Both works

Primary year:

Part of the original's full citation

Page:

Original's page as reported, then the secondary source's page

One paraphrase of Brandt (2004), read in Okafor and Lindqvist (2021), page 143.
ElementAPA 7MLA 9Chicago 18 notesChicago 18 author-date
Text citation(Brandt, 2004, as cited in Okafor & Lindqvist, 2021)Brandt … (qtd. in Okafor and Lindqvist 143)Note 1 with both works, joined by "quoted in"(Brandt 2004, 211)
Entry for BrandtNoneNoneYes, ending "Quoted in …"Yes, ending "Quoted in Okafor and Lindqvist 2021, 143."
Entry for Okafor & LindqvistYesYesYesYes
Connector capitalised?NoNoLowercase in notes, capital in the bibliographyCapital, starts a sentence
If the primary year is unknown(Brandt, as cited in …)No changeUse n.d. in the original's citationUse n.d. in the original's entry

A short checklist

Before you write as cited in, qtd. in, or quoted in

  • I searched for the original by DOI, title, and library catalogue, and I could not obtain it.
  • I named the original author in my sentence or parenthetical so the idea is credited correctly.
  • I used the connector for my style: as cited in (APA), qtd. in (MLA), quoted in (Chicago).
  • The page number in my citation is the page of the work I actually read.
  • APA or MLA: only the work I read is in my list. Chicago: both works are listed, and the original's entry carries the Quoted in sentence.
  • I did not write n.d. for the original in APA just because the secondary source omitted its year.
  • I will replace the chain with a direct citation if I obtain the original before submission.

Common mistakes

  • Listing the original in an APA or MLA list when you never read it. Both styles treat the list as a record of consultation.
  • Citing the original directly after reading only a summary. If the summary misreports it, the error is now yours, and a reader who checks will know.
  • Writing "cited in" or "quoted in" in APA. The APA phrase is as cited in.
  • Writing "as cited in" in MLA. The MLA abbreviation is qtd. in.
  • Giving the original's page numbers in APA or MLA. Give the page of the work you read.
  • Leaving out the secondary source's own entry in Chicago. Both works must be listed.
  • Using as cited in for a personal communication you received yourself. That is a personal communication citation, not a secondary one.
  • Filling a paper with chains because the textbook was convenient. Two or three are a judgement call; ten is a research problem.

Generate the outer citation, then add the chain

Cite the work you read as a normal book, article, or web page. The generator produces the reference entry and the author–date or author–page pair; you add as cited in, qtd. in, or quoted in and the original author's name by hand, because no generator can verify a source you have not opened.

In-text citation generator →Chicago footnote generator →DOI citation generator →

Frequently asked questions

What is a secondary source in a citation?
It is the work in which you read about another work. The original work is the primary source; the one you actually opened is the secondary source. This is a question of access, not of document type: a textbook summarising an experiment is a secondary source for that experiment even though a historian would also call the textbook secondary.
How do I write "as cited in" in APA 7?
Name the primary author and year, then the phrase as cited in, then the secondary source in normal author–date form: (Brandt, 2004, as cited in Okafor & Lindqvist, 2021). If the primary year is unknown, omit it rather than writing n.d. Only the secondary source appears in the reference list.
Does the original source go in my reference list?
In APA 7 and MLA 9, no; the list records only what you consulted. In Chicago 18, yes: the original gets a bibliography or reference-list entry that ends with a Quoted in sentence naming the secondary source, and the secondary source also gets its own entry.
What is the MLA abbreviation for a secondary source?
MLA 9 uses qtd. in, short for "quoted in," before the source you consulted: (qtd. in Okafor and Lindqvist 143). MLA uses the same abbreviation whether you are quoting or paraphrasing the original. Name the original author in your sentence so the parenthetical only has to identify where you read it.
Which page number do I use?
In APA and MLA, the page in the work you read, because that is the page your reader can check. In Chicago, the note gives the original's page as reported by the secondary source, then the secondary source's page: 211, quoted in …, 143. Never present a page you have not seen as if you had.
How does Chicago author-date handle a secondary source?
Cite the original in the text, for example (Brandt 2004, 211). In the reference list, the original's entry ends with "Quoted in Okafor and Lindqvist 2021, 143." and Okafor and Lindqvist get a normal entry of their own. Do not import APA's as cited in phrase into the Chicago parenthetical.
When is it acceptable to cite a secondary source?
When the original is out of print, unavailable through any library you can reach, or written in a language you cannot read, and when an unpublished document such as a letter is quoted in a published work. It is not acceptable simply because the textbook was closer to hand; a journal article with a DOI should be found and cited directly.
What if I find the original later?
Read the passage in context, cite the original directly, and add it to your list. Remove the secondary source unless you also cite it for claims of its own. Check that the summary you relied on was accurate; if the original says something different, revise your sentence, not just the citation.