What punctuation would you use in mentioning a company and its location (as in Microsoft, Redmond, WA) in running text? Isn’t it most common and natural to use commas? And yet, when it comes to giving the publisher and the place of publication of a book as part of a reference, many journals, including Science Editor, require you to use a colon, as in New York: Harper & Row or London: Penguin Books. The most common function of a colon is “to indicate a step forward from the first to the second—as when the second part explains the first part or provides an example”¹ or, to put it more simply, to signal that what follows a colon is an elaboration, a definition, an explanation, or an example(s) of the text that precedes the colon, as in “This brings us to possibly the most significant development of 2020: The prominence of science, and scientific publishing, in the minds of the general public.” In the examples given above, Harper & Row or Penguin Books is none of these things in relation to New York or London.

Another use of the colon in references that flies in the face of the recommendations made in usage guides is seen in references to chapters, as seen in the following example from the AMA Manual of Style,^2,p83 in which a colon follows the preposition “in”:

Boushey CJ. Application of research paradigms to nutrition practice. In: Coulston AM, Boushey CJ, Ferruzzi MG, eds. Nutrition in the Prevention and Treatment of Disease.

And yet, the very style manual cautions against such use of the colon^2,p458: “Avoid using a colon to separate a preposition from its object.” To be fair, the manual does explain this use of the colon to separate bibliographic elements within a bibliographic group.

Or, take the parentheses. Many journals, typically those from Europe and Britain, enclose the year of publication in parentheses. Now, that bit of information is certainly not incidental, not something to be glossed over; on the contrary, it is important information because it tells us how recent—or dated—the source in question is. So why put it within parentheses?

This article seeks to highlight the widening gap between the use of different punctuation marks as advocated in well-established style manuals and the increasingly idiosyncratic ways in which well-established international journals deploy the marks within references appended to scholarly articles and research papers. The format used by a few leading journals for references to papers published in journals is illustrated in the Table.

Table. Comparison of reference formatting by different journals.

To make it easier to compare the formats, the content, or the bibliographic details, remain the same. Although the original capitalization, typographic cueing (bold or italics), and journal titles (abbreviated or in full) have been retained in the examples reproduced in the Table, those details are irrelevant to this essay.

The Period

The use of the period in the examples in the Table ranges from the legitimate (to mark abbreviations—although skipped in example 6) through the optional (after the initials in author names) to the superfluous: all the examples use a period to mark the end of the reference—perhaps the only feature they share—but these references are not sentences at all, nor are the references ever run on like sentences within a paragraph. I wonder what purpose, if any, is served by that dot at the end.

The Semicolon

If there is one stop that can have no legitimate function in references, it is the semicolon simply because it is too subtle a stop to be deployed within so mundane a grouping as that of different elements that make up a bibliographic reference. The American Chemical Society uses it to separate the names of authors, using the semicolon as a “super comma”—a use most style manuals recognize. Casagrande,^3,p69 for example, says that a semicolon “can separates items in otherwise unwieldy lists, especially when the items listed contain their own internal commas.” However, if the commas used for separating the last name of an author from the author’s initials are dispensed with, the semicolon too can be ditched.

And do we really need the semicolon between the year of publication and the journal’s volume number? (examples 1 and 6 in the Table)? The relationship between the year and the volume number is at best accidental, the parts on either side of the semicolon are certainly not independent clauses, and neither part includes a comma.

Lastly, why skimp on the space that typically follows the semicolon in normal usage?

The Comma

Whereas the use of the comma to separate one author from the next is unexceptional, using one to separate the volume number from the inclusive page numbers is questionable. After all, these are neither items in a series (as in red, green, and blue) nor of equivalent status, a volume being a much larger unit because it contains dozens of individual papers, each with its page range.

On the other hand, in example 3 (Science), perhaps a heavier stop (a period?) is required to separate two distinct items, namely authors and the title of the paper, all the more so because a comma is also used to separate one author from the next.

Concluding Remarks

Let us reconsider how we should deploy punctuation marks in setting out references—these marks seem to have strayed, perhaps to serve some requirements of parsing the data—and it is time to bring them back into the fold as it were by making them conform to their standard functions in normal text to serve readers. In fact, now that we look up a cited document not by noting down the details given in the reference but simply by clicking, it is time that we reconsider not just the punctuation but the entire format for references—but that is another story and perhaps another article.

References and Links

1. Garner BA. The Chicago guide to grammar, usage, and punctuation, p. 361. Chicago: The University of Chicago Press; 2016.
2. Christiansen SL, Iverson C, Flanagin A, Livingston EH, Fischer L, Manno C, Gregoline B, Frey T, Fontanarosa PB, Young RK. AMA manual of style: a guide for authors and editors. 11th ed. New York, NY: Oxford University Press; 2020.
3. Casagrande J. The best punctuation book, period. Berkeley, CA: Ten Speed Press; 2014.

Yateendra Joshi, ELS (0000-0002-0410-4072), is a freelance copy editor.

Opinions expressed are those of the authors and do not necessarily reflect the opinions or policies of their employers, the Council of Science Editors, or the Editorial Board of Science Editor.