I've just read a paper that cited the same reference in two successive sentences:

This is the first sentence (xxxx 2013). This is the second sentence (xxxx 2013).

Up until now, I would have cited the reference just once, like this:

This is the first sentence. This is the second sentence (xxxx 2013).

Which method is correct?

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    "This is the first sentence (xxxx 2013). This is the second sentence." – Jukka Suomela Jun 8 '13 at 10:13
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    Wouldn't the term ibid apply? "This is the first sentence (xxxx 2013). This is the second sentence (ibid)." Or is ibid used only in end-notes and footnotes? – Paddy Landau Jun 8 '13 at 11:10
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    Ibid. is only used in certain styles of footnotes and endnotes. It is not used when directly citing works in the text (in MLA style, for instance). – aeismail Jun 9 '13 at 10:00
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    I have used loc. cit. in situations like these. – David Hill Nov 9 '14 at 22:47
  • In such situations, if it can be done, I'd just qoute the source rather than cite to it. Depends on what's easier. – Nick Jun 6 '15 at 4:01

In general terms, the reference should be made where the cited information occurs. If you cite in the second it is not clear from where the information in the first originates. A similar problem occurs if you cite an entire paragraph by adding a reference at the end of a paragraph ass "(Xxxx, 2013)" (I am fully aware that this is the norm in some fields).

Citing the same reference in two sentences is clearly wrong. The solution as I see it is to write the sentences so that it is clear they belong together. There are several ways to do this. One way is to avoid the passive, parenthetical, reference and use the active reference where only the year is in parenthesis. As an example, you can start the first sentence by stating "Xxx (2013) states ..." and then in the second say "They furthermore ...". In this example we provide a bridge between the two sentences so that it is very clear it is the same reference that applies. Instead of "They" you can also use "Xxxx".

There are clearly numerous ways to bridge sentences so the form depends on what you need to say. As a result I would recommend putting the reference in the first sentence, not the second.

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    Nice answer. Though I could imagine a situation where it is not "clearly wrong" to cite the same paper in two adjoining sentences because, e.g., you cite the same paper in two clusters of references like: yadda yadda yadda (xx1 2011; xx2 2011; xx3 2013). yadda yadda yadda (xx1 2011). – Thomas Jun 11 '13 at 7:04
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    +1 - As a general point, many citation questions seem to assume that the text cannot be changed, only the citations, when the citation issue could be more easily addressed by editing the text itself. Compare rasmussen.libanswers.com/a.php?qid=107534 – Oswald Veblen Dec 14 '14 at 13:01
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    @OswaldVeblen: I think that assumption is simply based on the issue that changing the text may fix the citation, but break something else at the same time. Maybe the text ended up exactly like it is because every synonymous version would not sound good in the complete context (reptitions of words etc.). Note that incidentally, in the example you linked to, the "good" version is also the longest one - just by one line, but one line can make a page count difference, and also, lines add up -, and space in a paper can be (depending on the field) a very sparse resource to save at all cost. – O. R. Mapper Dec 14 '14 at 15:19
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    @O.R.Mapper: every synonymous version? We're talking about a natural language here. Sometimes - in fact, often - the best way to fix a problematic paragraph is to delete it and write it again. Putting in citations as you go, and planning ahead for them, is key to good writing. "Avant donc que d’écrire, apprenez à penser." (Boileau 1674) – Oswald Veblen Dec 14 '14 at 15:26
  • @OswaldVeblen: Well, sure - and, as you go ahead in a systematical way, you usually try to consider all possible ways to express the intended statements. Some of those synonymous ways have to be ruled out because they don't fit in the context, and others remain. And sometimes, only one such version remains. The point is that citations do not need to "flow" grammatically in the sentence, and thus are still the most flexible part of the text to change, even when the sentences themselves are already restricted to a particular version based on the surrounding text or by the layout. – O. R. Mapper Dec 14 '14 at 15:50

Neither is correct, it is a matter of style.

Refer to the style guide of the journal, publishing house or conference that you're writing for.

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    If the style guide does not provide specific instruction for that matter, what then? Neither is correct or neither is incorrect? – scaaahu Jun 8 '13 at 7:52
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    Where style guides are silent, it is normally a matter for academic judgement. I would suggest that you either cite by sentence or by paragraph; rather than citing "all sentences prior to this citation." I come from a footnoting field though, your field will vary. – Samuel Russell Jun 8 '13 at 7:59
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    I disagree. In the second example the first sentence isn't properly cited (given only the info provided). – KennyPeanuts Jun 8 '13 at 12:50
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    @KennyPeanuts: the question of what counts as "proper" citation varies greatly depending on the field of study. In my field, it would be unusual to cite the same source more than once in a paragraph. – Oswald Veblen Dec 14 '14 at 12:59

This is exactly what the abbreviation "Ibid." is used for:

This is the first sentence (Xxxx, 2013). This is the second sentence (Ibid.).

It derives from the latin word "ibidem", which means "in the same place".

Source: https://en.wikipedia.org/wiki/Ibid.

Edit: Disclaimer

Following the comment discussion below this answer, I would like to state clearly that the usage of "Ibid." is highly dependent on the field of study and the general citation style you are using. If you have never encountered this abbreviation before in your field of study, you should probably not start using it.

  • In the Wiki page you linked: was cited in the preceding endnote or footnote. Are you sure your answer is correct? – scaaahu Dec 14 '14 at 12:36
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    Quoting from a bit further downstream of the article: "Ibid. may also be used in the Harvard (name-date) system for in-text references where there has been a close previous citation from the same source material.". So, since the OP seems to be using Harvard-style references, I guess the answer is yes. – carsten Dec 14 '14 at 12:50
  • The style manual determines whether "ibid." can be used. APA parenthetical citations look identical, but do not allow "ibid." blog.apastyle.org/apastyle/2014/07/does-apa-style-use-ibid.html – Oswald Veblen Dec 14 '14 at 14:46
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    As Oswald Veblen correctly points out, whether you actually do want to use "Ibid." depends on your academic discipline. Different academic fields use very different citation styles, and one should certainly stick with those conventions intrinsic to one's field of study. However, without knowing the field the OP is coming from, it's hard to give a definite answer. I was just stating that it is possible to use "Ibid." in such a case. – carsten Dec 14 '14 at 15:07
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    I've yet to see ibid. in Computer Science papers. I'd say your answer is misleading without some proper disclaimer. – Blaisorblade Dec 14 '14 at 17:27

What I would do in this case depends on whether you're citing two different claims/results or just two pieces of text within that paper related to the same claim/idea/point.

  • If it's two different results, definitely cite them separately, regardless of whether the citations are closeby or not; and I would make an effort to indicate, with each citation, the exact location of the specific claim/point, so it would be clear to the reader that these are two distinct claims. (If you're using LaTeX, it would look something like\cite[\S 1.2]{ThatXXXPaper} and \cite[Appendix B]{ThatXXXPaper}.)
  • If it's the same result/claim/point, and you're just citing the continuation of the text, take the advice in other answers, i.e.:

    • It may depend on the stylistic conventions in your field
    • It may depend on the stylistic conventions of the conference/journal to which you're submitting the paper, or your university's regulations if it's a thesis
    • You might want to use "ibid." (ibidem) instead of repeating the citation
    • You might be able to cite just once at the end of a paragraph (assuming that doesn't create ambiguity)
    • You might want to avoid the second citation by appropriate rephrasing as @PeterJanson suggests.

APA - Documentation does not need to be repeated for every idea within a single paragraph. For example, if you retrieved information for three consecutive sentences from the same source, you can put the information after the third sentence.


I think if you are writing something that refers to several sources repeatedly maybe you should use a different referencing system. Maybe use superscript numbers like the Vancouver referencing system.

I assume this is a problem more likely to be faced when writing a cohort / review paper.

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