Citation Styles

Chicago notes-bibliography system combines in-text notes with a bibliography at the end of a paper. Typically, this system is used within the arts, history and literature disciplines in the humanities. Whether one uses footnotes or endnotes, they are usually numbered to correspond with a superscript reference number in the text. Notes provide commentary on cited sources and unusual source types, making it easier for readers to reference certain sources.

Regardless of system, Chicago Manual of Style requires that "source citations must always provide sufficient information either to lead readers directly to the sources consulted or ... positively identify them, regardless of whether the sources are published or unpublished or in printed or electronic form."¹

You are required to note sources and include citations in the notes-bibliography citation system. Every resource noted in your paper must be listed alphabetically in the bibliography. Likewise, every resource in the bibliography must have at least one note appear in your paper.

• The exceptions are personal communications you've had with others, general mention of whole websites or periodicals, or general mention of common software and applications. While they have notes or mentions in the text, they are not included in the bibliography.
• Common knowledge is also not required to cite.

1. Chicago Manual of Style, "The purpose of source citations," in Chicago Manual of Style Online (Chicago: University of Chicago, 2017), chap. 14.1.

Both footnotes and endnotes use superscript numbers in the text, then a superscript or normal number next to the note. Formatting for full notes and shortened notes is the same between footnotes and endnotes. However, there are some differences when using footnotes and endnotes, including:

• Footnotes appear at the bottom (or foot) of a page, listing whatever sources were linked on that page.
• Footnotes are closely integrated into the text to make reading interesting or provide immediate knowledge of sources.
• Footnotes must begin on the page which they are referenced.
  • It can be difficult to fit longer footnotes onto one page, and it can be intimidating to have a page almost full of footnotes.
• Endnotes appear at the end of an article, at the end of a book chapter, or at the back of a book. They are before the bibliography.
• Endnotes do not appear on pages apart from the superscript numbers, eliminating page markup issues.
• Since endnotes are gathered in a list that can grow massive, it can be difficult to find one particular note.

If working with Chicago notes-bibliography style, check with your professor to see if you need to use footnotes or endnotes. 

Notes follow the format order of the author, title, and facts of publication. Commas separate all elements of a note, with parentheses enclosing any facts of publication. For the first mention of a source, the note is styled like running text:

1. Author, Title (Publisher location: Publisher, Date), Page. 

Subsequent mentions of the source need shortened note forms:

2.  Author Last Name, Title, Page. 

If the bibliography includes all works cited in the notes, all of the notes can be in shortened form. This way, readers can just go to the bibliography for full citations. However, if the bibliography isn't included or if all the works are not cited in the notes, then notes must be in full form for the first mention, then shortened in subsequent mentions. 

One to Three Authors: In full notes, authors are listed in standard order (first name last name). Use middle initials instead of spelling out the middle name. In shortened notes, use only the author's last name. Use "and" to separate two authors, as well as before the third author's name. 

Four or More Authors: For full and shortened notes, list the first author's last name followed by "et al."

No Author: If the author is unknown or not listed, the note should begin with a title. Follow formatting depending on the source type. If the author is listed as "Anonymous," use "Anonymous" as the author's name.

Punctuation: Commas separate all elements of a note, whether full or shortened. For full notes, parentheses enclose facts of publication. All notes end with a period. 

Italics and Underlining: Book titles, journal titles, and publication titles are italicized. Underlining is not used, including for DOIs or URLs.

Quotation Marks: Article titles, chapter titles, or other smaller works in a larger container are in quotation marks.

Abbreviations: Editions, editors, and translators are abbreviated to "ed.," "eds.," and "trans.," respectively. Issue numbers are abbreviated to "no.," but "vol." is not abbreviated for volumes. Shortened notes do not include abbreviations. 

Pagination: The abbreviations "p." and "pp." are not used for page numbers. Commas separate non consecutive pages while dashes show consecutive pages.

Indentation: No indents are needed for full or shortened notes in the text.

Digital Object Identifier (DOI): DOIs are unique numbers attached to scholarly journal articles or works. While DOIs are included in full notes, they are not included in shortened notes. 

URLs: While URLs are included in full notes, they are not included in shortened notes. 

Ibid.: Chicago style discourages use of the abbreviation "ibid." instead encouraging shortened citation. If pointing to something on the last cited source (whether it's the same page or a different page), you can omit the title. See 14.34 of Chicago Manual of Style Online for more information.
Example: 1. Morrison, Song of Solomon, 10.
                2. Morrison, 25. 

The 17th edition of Chicago notes-bibliography system has a bibliography list of all cited sources.

There are some differences with the format of bibliography entries when compared to full notes. In addition, there are formatting differences when comparing the bibliography list with APA's reference list and MLA's works cited list.

Title: On a new page after your paper, enter the word "Bibliography" and center it. Do not bold, italicize, underline or put quotation marks.

Order: Entries are organized alphabetically by the author's last name. If working with multiple sources by the same author or with works with no listed author, organize those sources alphabetically by title.

Indentation: The first line of each bibliography entry is flush left with the margin. Indent all subsequent lines by half an inch. 

Spacing: Unlike APA and MLA citation list entries, bibliography entries are single-spaced, with one line space in between entries.

Punctuation: All bibliography entries end with a period. Unlike notes (which use commas to separate most entry elements), periods separate most entry elements. Additionally, unlike notes, parentheses do not enclose publication information in bibliography entries. Colons follow the publication location, and commas follow the publisher before the publication year. 

Authors: The first-listed author’s name is inverted (last name, first name), but subsequent authors are listed as normal without a comma (first name last name). Include all authors in the bibliography, using "and" before the final author's name. Use middle initials instead of spelling out the middle name.

No Author: If the author is unknown or not listed, the note should begin with a title. Follow formatting depending on the source type. Do not alphabetize by articles (an, a, the). If the author is listed as "Anonymous," use "Anonymous" as the author's name. 

Capitalization: Capitalize each word in the titles and subtitles of articles, books, etc. Do not capitalize articles (a, an, the), prepositions or conjunctions unless it is the first word of the title or subtitle.

Italics and Underlining: The titles of books, magazine or newspaper publications, and journals are italicized. Underlining is not used, including for URLs and DOIs. 

Quotation Marks:  Enclose the title of articles, book chapters, presentations etc. in quotation marks. Use a period inside the closing quotation mark.

Abbreviations: Editions, editors, and translators are abbreviated to "ed.," "eds.," and "trans.," respectively. Spell out "edited by" and "translated by" if they're used. Issue numbers are abbreviated with "no.," but do not abbreviate volume numbers with "vol."  

Pagination: The abbreviations "p." or "pp." are not used to signify page numbers no matter the source type. Dashes are used for sequential pages, while commas are used for non-sequential pages.

Digital Object Identifier (DOI): A unique DOI is assigned to journal articles and always begins with a 10. DOIs provides persistent links to articles, eliminating issues with website URLs changing. However, not all articles have a DOI; additionally, DOIs are visible in some databases but "hidden" in others. If available, a DOI should be listed at the end of the citation. If there is no DOI present, omit that information

URL: A URL is used when a DOI is not used or found. If there isn't a DOI but the specific URL to the page makes it inaccessible, use the home page URL of the journal or book publisher. For articles, try to include the URL specifically leading to the article.