Incited about citations

As I discussed in my previous post, the most used indicator of a scientific paper’s impact is how often it is cited in subsequent papers. Consequently, one of the most important tasks when writing a paper is make sure that all of the key earlier works are properly named in the text. Not doing so is grounds for legitimate criticism from reviewers and readers; first, because it indicates that you have not done due diligence in your research in locating these papers and second, because you deny credit to the authors of the original paper. I have more than once had to gently inform an author that “you missed my contribution to the subject” or been embarrassed to have missed a key work. For many years, my email signature contained the sentence, “Those who do not know the literature are condemned to repeat it.”

A typical scientific paper may contain dozens or even one-hundred or more references. These occur in two places. Within the body of the text, there is usually a simple citation, giving the names of the authors and the year the paper is published. These link to the list of references, which give the full bibliographic information, so that the reader can find these papers if so interested.

Producing the citations and references may be the most time consuming and often frustrating parts of drafting the scientific paper. This is because nearly every scientific journal seems to have their own idiosyncratic way of formatting the in-text citations and the references, as laid out in their detailed “style guides”. I will illustrate this using my own papers (forgive the self-promotion).

In-text citations have a variable format, primarily depending on how many authors there are and if there are multiple citations at the same point. They also differ as to whether the name of the author is included in the main text. For example, using the style used by the journal Paleobiology:

An extremely clever paper on this is Plotnick (2017). This paper is almost as interesting as his much earlier work on the subject (Plotnick 1983). Other ingenious papers are Plotnick and Koy (2020) and Plotnick et al. (1996). And we should not forget his other memorable papers with his former students (Koy and Plotnick 2010; Hsieh and Plotnick 2020).

Note: et al. (et alia = and others) is usually used when there are three or more authors. Since papers can potentially have scores of authors, this is common.

This format is fairly standard, but there are variations in journals on the conventions of punctuation. For example, some may want a comma between the author and the year (Plotnick, 1983) or an ampersand between the names of authors when there are two of them (Plotnick & Koy, 2020). They may also want the order in multiple citations be alphabetical, rather than by publication date (Hsieh and Plotnick 2020; Koy and Plotnick 2010). Another option occurs in journals such as Science, where citations are indicated by superscripts in order of their occurrence in the text and do not include the author or year.

The variability in the in-text citations pales compared to the variability of formats for the papers in the reference list. There are strict requirements for how to reference books, papers in journals, chapters in edited multi-author volumes, etc. The differences among journals are of long-standing, and probably date to the publication of the very first issue.

Here are some examples of references for a paper, as used in a variety of journals:


Plotnick, R. E., and K. A. Koy. 2020. The Anthropocene fossil record of terrestrial mammals. Anthropocene 29:100233.


Plotnick, R. E., and Koy, K. A., 2020, The Anthropocene fossil record of terrestrial mammals: Anthropocene, v. 29, p. 100233.


PLOTNICK, R. E. and KOY, K. A. 2020. The Anthropocene fossil record of terrestrial mammals. Anthropocene, 29, 100233.


1. R. E. Plotnick, K. A. Koy, The Anthropocene fossil record of terrestrial mammals. Anthropocene 29, 100233 (2020).

All of these references contain the same material, but you can see the great variation in the order of information, the fonts, and the punctuation (note: there are no page numbers, since this was published online).

When submitting a paper, one must be careful to make sure to use the style specific to that journal. This is enough of a burden, but it gets worse if the paper is not accepted and ends up submitted elsewhere. All the in-text citations and references now to be reformatted. Ouch.

Thankfully, technology has come to the rescue. There are now available citation management programs, such as RefWorks, EndNote, and Zotero that automate much of this process. These programs let you build a library of citations, enter them into a paper, and then format for the journal you are using. Most journals have an automated output style for these programs, to produce the correct citations and reference. They are not perfect, so you still need to double check (or triple check) before submission, but they are still tremendous time savers. And I recently discovered that not all journals have an available output style. Still, they have helped me avoid my bête noire, missing references that I cite or not citing references I have in the bibliography (I still screwup sometimes).

That said, a pipedream of mine is that all journals come up with a common style. I was pleased to learn recently from Managing Editor Jessica Kastigar that the Journal of Paleontology in 2016 decided to abandon its own unique format and to adopt that used by the journals published by the Geological Society of America. I hope this begins a trend!



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Roy Plotnick

Roy Plotnick

Paleontologist, geologist, ecologist, educator. Professor at the University of Illinois at Chicago. Author of Explorers of Deep Time.