Learning how to cite a secondary source matters whenever you want to use an idea or quotation that you did not read in its original publication, but instead encountered described or quoted inside another author’s work. In academic writing, the source you actually read is the secondary source, and the original work you never saw firsthand is the primary source. Every major style, including APA, MLA, and Chicago, has a specific format for signaling this chain of evidence to your reader. The golden rule is simple: cite what you actually read, and make it transparent that the original idea came to you secondhand.
What a Secondary Source Citation Is
A secondary citation, sometimes called an indirect citation, happens when Author A is quoted or paraphrased inside a work by Author B, and you only have access to Author B’s work. You cannot honestly cite Author A directly, because you never read Author A. Instead, you credit Author A’s idea while pointing your reader to Author B, the source you genuinely consulted. This is different from a true primary versus secondary source distinction in research, where a secondary source analyzes primary material; here we are talking specifically about the citation mechanics of an idea reaching you through an intermediary.
The mechanics are consistent across styles. You name the original author in your sentence or in-text marker, then add a phrase that links to the work you read. Only the source you actually read goes in your reference list, works-cited page, or bibliography. The original author does not get a separate entry, because you cannot verify the details of a work you never examined. If you are unsure how this fits the broader picture, our overview of what a citation is explains the underlying logic of crediting sources.
APA: Use “as cited in”
In APA 7th edition, you name the original author in your text and use the phrase “as cited in” before the secondary source in the parenthetical citation. The reference list entry is for the secondary source only. Suppose you read a 2021 book by Marshall in which she quotes a 1998 study by Okonkwo. You never saw Okonkwo’s study, so you cite it this way.
Marshall, T. (2021). Foundations of learning theory. Example Press. https://example.com/foundations
In-text (parenthetical): (Okonkwo, 1998, as cited in Marshall, 2021).
In-text (narrative): Okonkwo (1998, as cited in Marshall, 2021) argued that early feedback accelerates retention.
Notice that only Marshall appears in the reference list. APA recommends including the original year if you know it, but if the secondary source does not give the original date, you can omit it. For more on building correct APA entries, see our APA format guide and the rules for APA in-text citations. You can also build the secondary-source reference automatically with the APA citation generator.
MLA: Use “qtd. in”
MLA 9th edition uses the abbreviation “qtd. in” (short for “quoted in”) inside the parenthetical citation. As with APA, the work you actually read is the one that appears on your works-cited page. Imagine you read an article by Delgado that quotes a statement by Hartley. You cite Hartley’s words but point to Delgado.
Delgado, Maria. “Rethinking the Archive in Digital Scholarship.” Journal of Modern Inquiry, vol. 14, no. 2, 2020, pp. 88-105.
In-text: Hartley insisted that “the document is never neutral” (qtd. in Delgado 92).
Name Hartley in your sentence, and let the parenthetical do the secondhand signaling. The page number belongs to Delgado’s article, the source you held in your hands. Review the MLA format guide and the details of MLA in-text citations for the surrounding rules, and use the MLA citation generator to format the works-cited entry.
Chicago: Use “quoted in”
Chicago 17th and 18th editions spell out “quoted in” within a footnote or endnote, and Chicago actively discourages secondhand citation unless the original is truly unavailable. In notes-bibliography style, your note credits the original author and then points to the source you read. Only the consulted source goes in the bibliography.
Bibliography: Calloway, Jonathan. Power and Persuasion in Early Rhetoric. Chicago: Example University Press, 2019.
Full note: 1. Wei Lin, “On Civic Speech” (1987), quoted in Jonathan Calloway, Power and Persuasion in Early Rhetoric (Chicago: Example University Press, 2019), 143.
Shortened note: 2. Lin, quoted in Calloway, Power and Persuasion, 143.
In Chicago author-date style, the parenthetical reads (Lin 1987, quoted in Calloway 2019, 143), and only Calloway appears in the reference list. See the Chicago style guide for note formatting, and generate the bibliography entry with the Chicago citation generator. Other styles handle this similarly: Harvard uses “cited in,” which you can format with the Harvard citation generator.
When to Avoid Secondary Citation
Secondhand citation is a last resort, not a shortcut. Instructors and editors generally expect you to track down the original source whenever it is reasonably available. Relying on an intermediary risks repeating that author’s misreadings, selective quoting, or transcription errors, and it weakens the authority of your argument. Before you settle for “as cited in,” try to locate the original.
How to find the original
Start with the secondary source’s own reference list, which should give you the full citation for the original work. Search your library database, Google Scholar, or an interlibrary loan service using the original author, title, and year. Once you read the original directly, cite it normally with no intermediary phrase, and the original work then becomes the entry in your reference list. Our guides on how to cite a journal article and how to cite a book walk through standard direct citations once you have the source in hand.
Secondary citation is most defensible when the original is out of print, in a language you cannot read, lost, or otherwise genuinely inaccessible. In those cases, using “as cited in” honestly reflects how the information reached you, which is more ethical than pretending you read something you did not. This honesty is also central to avoiding plagiarism.
Common Mistakes
The errors below trip up writers most often when handling indirect sources.
Citing the original as if you read it
The most serious mistake is dropping the intermediary phrase and citing the original author directly. This misrepresents your research and can constitute academic dishonesty if the original contains details you never verified.
Putting the original in the reference list
Only the source you actually read belongs in your reference page, works-cited list, or bibliography. Adding an entry for a work you never examined invents bibliographic data you cannot confirm.
Mixing up the phrasing by style
APA uses “as cited in,” MLA uses “qtd. in,” and Chicago uses “quoted in.” Using the wrong phrase signals carelessness, so match the convention to your assigned style. If you are juggling formats, our overview of citation styles explained and the comparison in APA vs MLA help keep the conventions straight.
Quick Tips
Always name the original author in your sentence so the reader knows whose idea it is. Keep the page number or year tied to the source you read, not the original. When in doubt about whether a source counts as direct or indirect, ask whether you personally opened and read it; if not, it is indirect. For everyday citing questions beyond this scenario, our broad guide on how to cite sources and the explainer on in-text citations cover the fundamentals.
Citing a secondary source well comes down to transparency. Credit the original thinker, point honestly to the work that carried the idea to you, and list only what you actually read. When you can, do the extra work to find and read the original, because direct citation is always stronger. When you cannot, the “as cited in,” “qtd. in,” and “quoted in” formulas let you stay accurate and ethical, and our citation generators can format the consulted source correctly in seconds.