Q. I find ISBNs extremely useful when trying to locate copies of books of interest, especially when searching for secondhand copies of out-of-print books, for requesting books on interlibrary loan, and for disambiguating common names or titles. I’m writing a literature review in the form of an annotated bibliography and would like to include ISBNs in the entries for those books that have them, as a convenience and finding aid for readers. I can’t find any guidance for inclusion of ISBNs in Chicago-style footnotes or bibliography entries, even as an optional item. Can you provide a recommended template or example of placement and formatting?
A. Sure. Here’s how we’d recommend adding ISBNs to the bibliography entries for three different editions of Daniel James Brown’s bestselling book about a rowing team’s quest for Olympic gold at the 1936 Berlin Olympics (listed here in chronological order, from the 2013 Viking hardcover to the 2023 Penguin Books movie tie-in edition):
Brown, Daniel James. The Boys in the Boat. Viking, 2013. ISBN 978-0-670-02581-7.
Brown, Daniel James. The Boys in the Boat. Penguin Books, 2014. ISBN 978-0-143-12547-1.
Brown, Daniel James. The Boys in the Boat. Movie tie-in ed. Penguin Books, 2023. ISBN 978-0-593-51230-2.
In general, an ISBN or other optional information may be added to an entry in a bibliography when needed, following the period at the end of the other citation data. But if you need to include an ISBN within a note, we’d suggest adding it in parentheses, as part of the facts of publication:
1. Daniel James Brown, The Boys in the Boat, movie tie-in ed. (Penguin Books, 2023; ISBN 978-0-593-51230-2), 33–34.
The hyphens in the ISBN, which are optional, will help those who need to manually copy or type the number. For more on ISBNs and how they work, start with CMOS 1.36 and these FAQs from ISBN.org.
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. Hello, Chicago doesn’t seem to have an example of how to cite a contribution to a new edition of a book. Should the edition number follow a period or comma in the reference list entry below? Though my example is in Chicago 17 style, the question is still relevant for Chicago 18 style, so I would appreciate your guidance. Thanks!
Rothbard, Murray N. 2006. “The Libertarian Heritage: The American Revolution and Classical Liberalism.” In For a New Liberty: The Libertarian Manifesto, 1–23. 2nd ed. Auburn, AL: Ludwig von Mises Institute.
A. The best place for an edition number for a book is usually just after the title. When it’s part of an “In . . .” statement (as in your example), it follows a comma. As of the 18th edition, Chicago no longer requires a page range for a chapter or other contribution to a book or a place of publication, so your author-date entry would look like this:
Rothbard, Murray N. 2006. “The Libertarian Heritage: The American Revolution and Classical Liberalism.” In For a New Liberty: The Libertarian Manifesto, 2nd ed. Ludwig von Mises Institute.
(If you were following CMOS 17, the edition number would precede the page range: “. . . Manifesto, 2nd ed., 1–23. . . .”) In a reference list entry for the book as a whole, the edition number would follow a period:
Rothbard, Murray N. 2006. For a New Liberty: The Libertarian Manifesto. 2nd ed. Ludwig von Mises Institute.
Bibliography entries would follow the same pattern (except for the placement of the year of publication; see CMOS 14.1).
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. Why is ibid. preferable to id.? The meaning is essentially the same and id. is more succinct, and it is used extensively in legal citation without any apparent confusion or misunderstanding.
A. What you say is true. But because id. (idem, the same) is used mainly in legal citations whereas ibid. (ibidem, in the same place) has long been preferred in history and most other academic disciplines, ibid. is much more well known than id. Whether ibid. also benefits from not looking like id (the complement to the ego and superego) is anyone’s guess.
For more on ibid. and id. (including Chicago’s preference for shortened citations over either of those abbreviations), start with CMOS 13.38.
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. How would you cite a website home page in a bibliography? Would the page title be “Home Page” (in quotes) or just a descriptive “Home page” (no quotes)? Or the title of the website? Or something else entirely?
A. A home page is almost never titled “Home Page,” so a description is your best option (though you can leave that out if it’s obvious from the URL and the other information in your citation). Note also that a home page isn’t normally a source that you’d list in a bibliography; consider limiting your citation to a mention in either the text or a note (though we’ll show the form for a bibliography entry here).
Wherever you cite it, you should save a version of the page as it existed when you consulted it. Unlike a published article or other content that may be available from a home page, a home page itself is designed to change over time (i.e., as a site adds content or to keep up with new software, or both).
If it is important to share this version with your readers, use the Internet Archive’s Wayback Machine or a similar service to create a public link and cite that version as follows:
University of Chicago Press (home page). Archived November 27, 2024. https://web.archive.org/web/20241127140410/https://press.uchicago.edu/index.html.
That’s the page at https://press.uchicago.edu/index.html as it existed on November 27 at four minutes and ten seconds after two in the afternoon UTC (the string of numbers in the middle of the URL; that link points to the page as saved using the Wayback Machine’s Save Page Now feature). If you do not cite an archived version, you will need to include an access date. For more details and examples, see CMOS 14.104. For the meaning of UTC (Coordinated Universal Time), see 10.47.
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. How should one cite a published book that is in an archival (personal papers) collection? The most important element of the book is not the text but the annotations added by the person whose collection the book is in. Thanks!
A. Cite the book like any other book; then cite the archive according to the advice and examples in CMOS 14.119–29, prefacing this information with “in” if it immediately follows the book citation (cf. CMOS 13.25).
The goal is to make it clear which book you’re citing and where the copy that has the annotations can be found. The annotations themselves can be discussed anywhere—in your text, in your notes, or in an addendum to a bibliography entry for the book (see CMOS 13.68, item 3)—and you can cite specific page numbers where applicable. But the annotations wouldn’t be cited as a separate entity.
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. If an author insists on using a widely attributed quote whose source cannot be confirmed, how should I cite it? Should I cite it at all? Or should I simply note in the running text that the quote is “widely attributed to such and such”?
A. Your last idea is the best one. In general, if the source of a quotation can’t be confirmed, this fact should be stated in the text that introduces it instead of being relegated to a note, where readers might miss it. The phrase “widely attributed” should make it clear that the attribution isn’t definitive; however, if the author can provide one or more sources that back up this claim, those could be (and in an academic work should be) provided in a note.
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. If a sentence includes quotations from different pages which are out of order (say a quotation from page 11 and then a quotation from page 3), should the citation in the footnote list the pages chronologically or in the order in which the quoted material appeared in the sentence?
A. The order of specific page number references in a footnote should correspond to the sequence of quotations in the sentence. The logic is the same as it is for multiple references to different sources in the same note, which, according to CMOS 13.61, “must appear in the same order as the text material (whether works, quotations, or whatever) to which they pertain.” But multiple sources in a note are usually separated by semicolons; multiple page numbers, unless they’re expressed as a range, are usually separated by commas (as shown in 13.22).
[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]
Q. Does CMOS have an opinion or suggestion on how citations should occur within PowerPoint slides and in similar presentation software? Many classes and research presentations now rely on these types of presentations, but it’s not clear what the expectations for citations are. Are references at the end sufficient, or should there be a version of footnotes throughout? Perhaps only for direct quotes and the like? Thanks!
A. In most cases, a slide or two of references at the end of the presentation would work well. These could be formatted like a bibliography or reference list at the end of a book or article. But if the slides won’t be made available to consult after the presentation (e.g., as a handout or as a downloadable file), consider using footnotes on individual slides instead.
In the case of a direct quotation or specific data points, it’s usually best to credit whoever is responsible for the words or data on the applicable slide—for example, in a brief attribution complemented by a fuller source citation at the end of the presentation.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Editing an anthology of academic nonfiction, I find a source citation for a video on YouTube. When I paste the URL into my browser, I get the “This video isn’t available anymore” page. General searches on the associated subjects of the video don’t turn up anything, and the author can’t find it, either. What should I do? Can we cite a ghost source, with a note indicating that it has vanished? Or do we have to jettison the source citation and associated quotations?
A. You say it’s an anthology, which would generally mean that the article or essay or whatever would have been previously published. In that case, we’d recommend leaving both the text and citation as originally published; then, to save readers the trouble of chasing after a bad link, you could add “[video no longer available]” or the like in square brackets after the original citation (see also CMOS 2.44 and 6.99).
If, however, you were editing a previously unpublished document, then it would be better to revise the text to eliminate any reliance on the video (or ask the author to do so). To avoid this unfortunate scenario, authors should always save a copy of any source that might be subject to disappearing—for example, via the Save Page Now feature at the Internet Archive’s Wayback Machine. (The forthcoming CMOS 18 will show how to cite a source that’s been archived in this way. Or see this recent Q&A for an example.)
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. I am citing an author who has two last names. The first is her maiden name, and the second her married name. I am aware that, ordinarily, one should go by the second surname. However, I am citing articles by this author from both before and after she was married, meaning that some of her articles only have the first last name and some have both last names. In this circumstance, what is the best way to cite her in both footnotes and in the final bibliography?
A. In the bibliography, cite the work as it was published; to help readers find both versions of the same name, you can include cross-references from one form to the other. For example, if you were to cite a book and an article by Hillary Clinton, you might include the following entries:
Under C:
Clinton, Hillary Rodham. It Takes a Village: And Other Lessons Children Teach Us. New York: Simon & Schuster, 1996.
Clinton, Hillary Rodham. See also Rodham, Hillary.
Under R:
Rodham, Hillary. “Children under the Law.” Harvard Educational Review 43, no. 4 (1973): 487–514.
Rodham, Hillary. See also Clinton, Hillary Rodham.
That’s the form for a bibliography. In a note that cites the earlier source, you could clarify for readers (parenthetically or otherwise) that it was published under the name Hillary Rodham.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]