A secondary citation occurs when you refer to a source you have not read yourself, having encountered it only through another author’s discussion. Scholarly convention requires you to be transparent about this using the “as cited in” (or “qtd. in”) formula. The guiding principle is simple: cite what you actually read, and wherever possible track down and cite the original source instead.
Why the rule exists
If author B quotes or summarises author A, and you have read only B, you cannot vouch for what A really said. B may have paraphrased loosely, quoted selectively or made an error. Citing A directly as if you had read it misrepresents your sources and risks propagating a mistake. The “as cited in” convention keeps the record honest by showing the reader the chain: the original idea came from A, but you read it in B. This honesty is part of the integrity of the scholarly record.
Read the original where you can
Secondary citation is a fallback, not a convenience. Before using it, try to obtain the original — through your library, interlibrary loan, or a DOI lookup. Reading the original lets you confirm the quotation, see its context and cite it directly. Use “as cited in” only when the original is genuinely unavailable (out of print, untranslated, lost).
How major styles handle it
The styles agree on the principle but differ in wording and in which source goes in the reference list. The general rule across styles is that the reference-list entry is for the work you actually read (the secondary source).
| Style | In-text form | Reference list |
|---|---|---|
| APA | (Smith, 1999, as cited in Jones, 2020) | Jones (the source you read) only |
| MLA | (qtd. in Jones 45) | Jones (the source you read) only |
| Chicago (notes) | Smith, [work], quoted in Jones, [work] | Both may appear, with the relationship shown |
| Harvard (author–date) | (Smith 1999, cited in Jones 2020) | Jones (the source you read) only |
Always confirm the exact punctuation against your specific style edition, as details vary between versions. A reference manager can format the entry, but secondary citations are a classic case where you must check the output by hand.
Worked examples
APA, in text: Early work on data reuse argued that incentives drive deposit (Smith, 1999, as cited in Jones, 2020). Only Jones (2020) appears in your reference list.
MLA, in text: One critic calls the dataset “the backbone of reproducibility” (qtd. in Jones 45). Only Jones appears on the Works Cited page.
In both cases the message to the reader is identical: the idea originates with Smith, but you read it in Jones, and Jones is what you can actually verify. For how this fits into building a full reference list, see our guide to compiling a bibliography.
Good practice
Minimise secondary citations; prefer originals; quote B’s reading of A accurately; and never silently cite A as if you read it. When you must use “as cited in”, be precise about page numbers from the source you read. These habits, alongside accurate reference checking, support honest scholarship. See our author resources, the dictionary and the research-outputs hub for more.
Frequently asked questions
What does ‘as cited in’ mean?
It signals that you are citing an original source (the primary) that you encountered only through another work (the secondary) which you actually read. It keeps your sourcing honest by showing you did not read the original directly.
Which source goes in my reference list?
In most author–date styles, only the source you actually read — the secondary source — appears in the reference list. The original is named in the in-text citation but not listed, because you cannot verify it directly. Chicago notes style may show both.
Is using ‘qtd. in’ the same as ‘as cited in’?
Effectively yes. “Qtd. in” (quoted in) is the MLA wording, while “as cited in” is the APA and Harvard wording. Both indicate a secondary citation; use the form your style requires.
When should I avoid secondary citation entirely?
Whenever you can obtain the original. Reading the primary source lets you verify the quotation and context and cite it directly, which is always preferable. Reserve secondary citation for sources that are genuinely unavailable.
