At some point it happens to everyone who writes academically: you need a statement by Mueller (1923), but all you have on your desk is a book by Schmidt (2020) that cites Mueller. The temptation to simply take Mueller at second hand is real. This is exactly where the secondary citation begins — and with it a whole set of error sources that can cost you dearly in the final stretch of a thesis.
What is a secondary citation?
A secondary citation arises when you cite source A that you have never held in your hands — you only know it through source B, which cites or paraphrases A. In practice: you take Mueller’s statement as Schmidt renders it, and you flag that in your reference.
The academic ground rule is firm but important: secondary citations are the exception, not the rule. The standard path in any serious academic work is to obtain the original source, read it yourself, and cite from it directly. Using secondary citations freely signals to the examiner: research was shortcut, not conducted.
When is a secondary citation acceptable?
There are four classic situations in which departments will tolerate a secondary citation:
- The original is out of print or physically inaccessible — for example a book from the 1920s held only in a single archive.
- The original is in a language you do not know, and no translation exists — for example a Russian-language study covered in the English-language secondary literature.
- The original is a historical manuscript with archive restrictions or no digital copy.
- The cited statement is central to your argument, cannot be replaced by a more accessible source, and you have made a demonstrable attempt to obtain the original.
If even one of these conditions is not met, the rule applies: obtain the original, do not shortcut.
How does a secondary citation look in practice?
The format is similar across common styles (Harvard, APA, footnotes). You name the original source first, then add the formula “cited in” followed by the secondary source you actually read.
Harvard (in-text):
According to Mueller (1923), the procedure was “fundamentally unstable” (cited in Schmidt 2020, p. 14).
APA 7 (in-text):
(Mueller, 1923, cited in Schmidt, 2020, p. 14)
Footnotes (humanities tradition):
Mueller, Hans: Foundations of Mechanics, Berlin 1923, p. 47, cited in Schmidt, Anna: Classics of Mechanical Physics, Zurich 2020, p. 14.
The key question is: which source goes in the bibliography? Answer: Schmidt — the secondary source, because that is the one you physically read and can stand behind. Mueller does not appear in the bibliography unless your department explicitly requires it (as is sometimes the case in certain humanities disciplines).
The risks of secondary citations
This is where it gets serious. A secondary citation is not just a stylistic weakness — it is a systematic risk to the accuracy of your work. Three problems come up again and again:
1. Content distortion — the classic false-citation path
Schmidt summarises Mueller in two sentences. That summary is never a 1:1 rendering — it is a simplification, a selection, an interpretation. When you take Schmidt’s account as Mueller’s own words, you amplify that simplification, and the examiner finds on spot-checking that Mueller never actually wrote that. This is exactly the transition from secondary citation to false citation, and exactly where you lose marks. More on this in the post Plagiarism vs. false citation.
2. Outdated secondary literature
Schmidt (2020) may cite Mueller (1923) in a way that current research has long since corrected. If you adopt Schmidt’s reading uncritically, you carry a century-old state of knowledge into your thesis without noticing.
3. Error chains
If Schmidt gives a wrong page number, you have it too. If Schmidt got the year of publication wrong, the error lands in your bibliography. Secondary citations pass on every mistake in the secondary source directly to you.
How to track down the original
Before you give up and resort to a secondary citation, work through these options:
- Interlibrary loan. In Switzerland via swisscovery/SLSP, in Germany via the KVK or your university’s interlibrary loan service. Even books from the 1920s usually arrive within two weeks.
- Google Scholar and ResearchGate. Many original texts are freely available as preprints or author versions.
- Open-access versions. For articles from the last 15 years, often available directly on the publisher’s website or the authors’ institutional repository.
- Contact the authors directly. A polite email to the correspondence address of a study surprisingly often yields the PDF — researchers are glad when their work is read.
- Sci-Hub and similar shadow libraries exist but operate in a legal grey zone. Not recommended, and not something you would mention in an academic methods section.
In 80 percent of cases you have the original after 20 minutes of searching. Then you no longer need the secondary citation.
Three complete examples
Example 1 — Social sciences (APA 7)
You are writing a bachelor’s thesis on trust in institutions and need a statement from Luhmann (1968), but only have the edited volume by Endress (2012) to hand.
In the running text:
Luhmann describes trust as a “mechanism for reducing social complexity” (Luhmann, 1968, cited in Endress, 2012, p. 87).
In the bibliography (Endress only):
Endress, M. (2012). Sociological Theories of Trust. Wiesbaden: Springer VS.
Example 2 — Engineering / Fluid mechanics (Harvard)
In your master’s thesis on fluid mechanics you need a historical statement by Prandtl (1904), but can only obtain the textbook by Spurk (2010).
In the running text:
Boundary layer theory postulates that friction effects are confined to a thin layer close to the wall (Prandtl 1904, cited in Spurk 2010, p. 23).
In the bibliography:
Spurk, J. (2010): Fluid Mechanics: An Introduction to the Theory of Fluid Flows. 8th ed., Berlin: Springer.
Example 3 — History (footnote)
You are working with a chronicle fragment from the fourteenth century held only in an archive in Florence. You cite it from an edition by Bauer (1998).
In the footnote:
Chronica Florentina, fol. 12r, cited in: Bauer, Reinhard: Florentine City Chronicles of the Trecento, Munich 1998, p. 102.
In the bibliography:
Bauer, Reinhard: Florentine City Chronicles of the Trecento, Munich 1998.
Secondary citation allowed vs. not allowed — an overview
| Scenario | Original obtainable? | Secondary citation OK? |
|---|---|---|
| Current article in Nature, behind a paywall | Yes, via university library | No |
| Russian-language study with no available translation | No | Yes, with “cited in” |
| 1923 book, held by 30 libraries | Yes, via interlibrary loan | No |
| Medieval manuscript, restricted archive access | No | Yes, with “cited in” |
| Standard reference held by every university library | Yes | No |
| Out-of-print work, no digital copy, unavailable second-hand | No | Yes, with “cited in” |
| Source “famous” only through secondary literature | Usually yes, with some searching | No |
Common mistakes with secondary citations
Three patterns examiners see — and penalise — regularly:
1. Disguising the secondary citation. You write “(Mueller 1923, p. 47)” as if you had read Mueller yourself, when all you know is Schmidt’s account. If this is caught — and it happens more often than you might think, because examiners know the secondary literature — it counts as an attempt at deception.
2. Omitting the secondary source. Secondary citation in the running text, but only Mueller appears in the bibliography, not Schmidt. This conceals where you actually obtained the information and makes the claim untraceable.
3. Too many secondary citations. If a third of your central references contain “cited in”, that is no longer a style issue — it is a methodological one. The thesis reads as though no primary sources were consulted.
Acurio as a safety net
Sometimes you have managed to obtain the original after all — and the question is whether your secondary citation (or your new direct reference) correctly renders what the source actually says. This is exactly where Acurio comes in. You upload your DOCX and your source PDFs, Acurio checks every reference against the original and reports back whether the claim is genuinely supported. Especially for statements you originally knew only from a secondary source, this cross-check against the original is the step that protects you from a false citation.
Conclusion
A secondary citation is a last resort with clear rules: only when the original is genuinely inaccessible, formatted correctly with “cited in”, and always with the awareness that you are taking Schmidt’s reading of Mueller — not Mueller himself. Using secondary citations as a shortcut systematically builds false citations into your work. Deploying them as a conscious, well-justified exception, on the other hand, demonstrates methodological maturity.