Secondary citation (“as cited in”)
Also called: as cited in, indirect citation, secondary source citation
Citing a source you have only read about in another source, by naming both and marking that you did not see the original.
If Okafor quotes a 1974 study you could not obtain, you cite it as “(Moreau, 1974, as cited in Okafor, 2019)” and put only Okafor — the source you actually read — in your reference list. The point of the construction is that it does not claim you read Moreau.
Treat it as a last resort. A secondary citation inherits every error in the intermediary's reading, and reviewers notice when a chain of them substitutes for finding the original. Use it when the original is genuinely unavailable — out of print, untranslated, lost — and say so if it matters.
See also
Primary sourceA direct, first-hand record of the thing you are studying, rather than someone else's account of it.Secondary sourceA source that describes, analyses, or interprets primary material rather than presenting it directly.In-text citationA short pointer placed in the body of your paper that identifies which source a statement came from and sends the reader to the full reference.