When an author you’re reading quotes or references someone else’s work, and you want to use that original idea, you create what’s called a secondary source citation (sometimes called an indirect citation). The key principle across every major style is the same: you credit both the original author and the source where you actually found the information, and your reference list or bibliography only includes the source you read yourself. The exact phrasing differs by style, so here’s how to handle it in APA, MLA, Chicago, and Harvard.
When to Use a Secondary Citation
A secondary citation is appropriate when you can’t access the original source directly. Maybe the original is out of print, behind a paywall you can’t get through, written in a language you don’t read, or simply not available through your library. Every major style guide discourages relying on secondary citations when you could track down the original. If you can find the original work, cite it directly instead. But when you genuinely can’t, a secondary citation is the correct approach.
APA Style (7th Edition)
APA uses the phrase “as cited in” to flag a secondary source. In the text, name the original author, then write “as cited in” followed by the author you actually read.
For example, say you’re reading a 2020 article by Lyon et al. that quotes a 1993 study by Rabbitt. You’d write:
- Rabbitt (1993, as cited in Lyon et al., 2020) found that…
In your reference list, you only include the source you actually read. In this case, that means Lyon et al. (2020) gets a full reference entry. Rabbitt (1993) does not appear in the reference list at all. The in-text citation gives your reader enough information to locate the original through Lyon’s work.
MLA Style (9th Edition)
MLA uses the abbreviation “qtd. in” (short for “quoted in”) inside the parenthetical citation. You can place the original author’s name either in your prose or inside the parentheses.
Option one, with the original author named in your sentence:
- According to Alexander Pope, “A little learning is a dang’rous thing” (qtd. in Damrosch 239).
Option two, with everything inside the parentheses:
- “A little learning is a dang’rous thing” (Alexander Pope qtd. in Damrosch 239).
On the Works Cited page, you list only the source you actually consulted. In this example, Damrosch’s book gets a full entry. Pope’s original work does not.
Chicago Style
Chicago uses the phrase “quoted in” and handles secondary citations through its footnote or endnote system. The Chicago Manual of Style explicitly discourages this practice, noting that authors are expected to examine the works they cite, but allows it when the original is unavailable.
In a footnote, you provide the full citation of the original work, then follow it with “quoted in” and the full citation of the secondary source:
- 1. 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.
Notice that Chicago is the exception to the “only list the source you read” rule. Both the original and the secondary source appear in the note, giving the reader a complete trail. In your bibliography, include at minimum the source you consulted, and ideally both works.
Harvard Style
Harvard referencing uses either “quoted in” or “cited in” depending on whether the secondary author was directly quoting or summarizing the original. This is a distinction the other styles don’t make explicitly.
If the secondary source directly quotes the original author, use “quoted in”:
- West et al. (2007, quoted in Birch, 2017, p. 17) state that…
If the secondary source paraphrases or summarizes the original, use “cited in”:
- Positive identity can be affirmed in part by a supportive family environment (Leach, 2015, cited in The Open University, 2022).
Your reference list includes only the source you actually read. In the first example, Birch (2017) gets a full reference. In the second, The Open University (2022) does. The structure of those reference entries doesn’t change at all from a normal citation.
Quick Reference by Style
- APA: “as cited in” in the text; reference list includes only the secondary source
- MLA: “qtd. in” in parentheses; Works Cited includes only the secondary source
- Chicago: “quoted in” in the footnote; both sources appear in the note
- Harvard: “quoted in” or “cited in” in the text; reference list includes only the secondary source
Making It Work in Practice
Before you settle for a secondary citation, spend a few minutes trying to find the original. Search your library database, Google Scholar, or even the references section of the source you’re reading. If the original is freely available, citing it directly is always stronger. Professors and editors notice when writers lean on secondary citations for sources that are easy to find.
When you do use a secondary citation, make sure you’re representing the original author’s ideas accurately. You’re trusting the secondary author’s interpretation or transcription, and mistakes can carry forward. If the quote or idea is central to your argument, that’s another reason to track down the original when possible.
One more thing to keep in mind: some instructors limit how many secondary citations they’ll accept in a paper. If your assignment doesn’t specify, keeping them to a minimum signals stronger research skills and makes your work more reliable overall.