The Author-Date style is primarily used in the sciences and social sciences. It has two major differences compared to the Notes and Bibliography Style:
The sciences and social sciences place greater importance on how recent a source is that the humanities. The Author-Date system of Chicago allows the dates of sources to be emphasized in a way that the Notes-Bibliography style does not.
Like the Notes and Bibliography style, the reference list (commonly titled "References" or "Works Cited" in Author-Date style) is included at the end of the paper. This section of a paper lists all sources cited in the paper in alphabetical order, and contains more publication details than the in-text citations.
The following tabs on this page present examples, templates, and brief explanations for the proper use of Author-Date style. More detailed information about the use of the Author-Date style can be found:
The Chicago Manual of Style, 18th Edition by Note that the heading on this page says "Bibliography," centered on the page and in normal font.
Photo: Chicago Bibliography Sample from Lumen Learning (n.d.). Retrieved April 19, 2021, from https://courses.lumenlearning.com/boundless-writing/chapter/chicagoturabian-citations-and-references-notes-and-bibliography-nb-system/
Place the author's last name, date, and page number within brackets in the text. The citation is placed after the quote or paraphrased material and before the punctuation marking the end of the sentence. Pay attention to the placement of punctuation in the following examples.
"your quote here" (Lerner 2009, 99).
Place "and" between the two authors' names.
Your paraphrased sentence here (Ward and Burns 2007, 52-54).
*note: to cite a page range, include a dash between the start page and end page as shown above.
Include the name of the first listed author followed by "et al." starting from the very first time the source is cited.
(Schonen et al. 2024, 276).
You may use an organization's name in an abbreviated form to shorten in-text citations. Note that when you use the abbreviation, it is the abbreviation (not the spelled-out name) that will lead in the reference list.
(ISO 1997)
ISO (International Organization for Standardization). 1997. Information and Documentation - Rules for the Abbreviation of Title Words and Titles of Publications. ISO 4.
For more details, consult the Chicago Manual of Style, 18th Edition, Section 13.123 ("Author-date text citations of works with more than two authors").
The only difference between Notes and Bibliography and Author-Date with regard to bibliography entries is the placement and formatting of the year: Author-Date places the year immediately after the authors' name(s) and does not put brackets around it. Note also that the first author's name in any bibliography entry is inverted (Last name, First name Middle name) and subsequent names are not inverted (First, Middle, then Last name) as shown in the examples below.
Last name, First name M., and First name M. Last name. Year. "Title of Article." Journal Title volume, no. issue (issue month/season, if applicable): first page - last page. doi.
***Note: that the last number before the pages in in parenthesis. I.e., if there is no month/season, the issue number is in brackets. If there is neither a season nor an issue number, the volume number is in brackets.
Kossinets, Gueorgi, and Duncan J. Watts. 2009. "Origins of Homophily in an Evolving Social Network." American Journal of Sociology 115, no. 2: 405-50. http://doi.org/10.1086/599247.
Use a URL instead of a DOI.
Whitney, Frank P. 1929. "The Six-Year High School in Cleveland." School Review 37, (4): 267-71. http://www.jstor.org/stable/1076243.
List all of the authors' names.
Fulcher, Karyn, Meriah Drabkin, Jennifer Gibson, Jenny Francoeur, Abbey Eurchuk, Maria Weaver, Bobbi Turner, and Nathan J. Lachowsky. 2021. "Contraceptive decision-making and priorities: What happens before patients see a healthcare provider." The Canadian Journal of Human Sexuality 30, (1): 56-64. http://muse.jhu.edu/article/791387.
List the first three authors followed by "et al."
Anand, Sonia S., Sylvia Abonyi, Laura Arbour, et al. 2018. "Canadian Alliance for Healthy Hearts and Minds: First Nations Cohort Study Rationale and Design." Progress in Community Health Partnerships: Research, Education, and Action 12, (1): 55-64. http://doi.org/10.1353/cpr.2018.0006.
For more details, consult the Chicago Manual of Style, 18th Edition. Section 14.67 begins the discussion and examples for journal article entries. Keep and eye open for "author-date" variations and details.
The only difference between Notes and Bibliography and Author-Date with regard to bibliography entries is the placement and formatting of the year: Author-Date places the year immediately after the authors' name(s) and does not put brackets around it. Note also that the first author's name in any bibliography entry is inverted (Last name, First name Middle name) and subsequent names are not inverted (First, Middle, then Last name) as shown in the examples below.
***Note: previous editions of CMOS included a place of publication before the publisher. In the 18th edition, however, the place of publication is no longer required.
Last name, First name, and First name last name. year. Title of Book, number of Edition. Publisher.
Lerner, Fred. 2009. The Story of Libraries: From the Invention of Writing to the Computer Age, 2nd ed. Continuum.
(Lerner 2009, 23)
Sterling, Terry Greene, and Jude Joffe-Block. 2021. Driving while Brown: Sherriff Joe Arpaio Versus the Latino Resistance. University of California Press.
(Sterling and Joffe-Block 2021, 110)
List up to six authors. If there are more than 6, list only the first three followed by "et al."
Sechzer, Jeri A., Sheila M. Pfafflin, Florence L. Denmark, Anna Griffin, and Susan J. Blumenthal, eds. 1996. Women and Mental Health. John Hopkins University Press.
If the text has a contributor (editor(s), compiler(s), or translator(s)) listed and no author, the contributor(s) appear at the beginning of the entry followed by the appropriate abbreviation ("ed." or "eds.", "comp." or "comps", or "trans.").
***Note: the abbreviation for editor, compiler or translator are not included in the in-text citation
LaFollette, Hugh, ed. 2014. Ethics in Practice: An Anthology, 4th ed. Wiley Blackwell Press.
(LaFollette 2014, 274)
***Note: If there is no author and no contributor mentioned. begin with the title instead of the author. If the text has a long title, you can use a shorted version of title for the in-text citations.
A True and Sincere Declaration of the Purpose and Ends of the Plantation Begun in Virginia, of the Degrees Which It Hath Received, and Means by Which It Hath Been Advanced. 1610. London.
(True and Sincere Declaration 1610)
***Note: Chicago 18 no longer requires that the page range for a chapter in an edited book be included in the reference entry.
Ellet, Elizabeth F. L. 1968. "By Rail and Stage to Galena." In Prairie State: Impressions of Illinois, 1673-1967, by Travelers and Other Observers, edited by Paul M. Angle. University of Chicago Press.
Obama, Michelle. 2018. 2018 Becoming. Crown. Kindle.
Shakespeare, William. n.d. A Midsummer Night's Dream Folger Shakespeare Library. PDF.
For more details, consult the Chicago Manual of Style, 18th Edition. A discussion of books begins in sections 14.2. Keep an eye open for Author-Date details and specifications.
The only difference between Notes and Bibliography and Author-Date with regard to Bibliography entries is the placement and formatting of the year. Author-Date places the year immediately after the authors' names and does not put brackets around it.
Note also that the first author's name in any bibliography entry is inverted (Last name, First name Middle name) and subsequent names are not inverted (First, Middle, then Last name) as shown in the examples below.
***Note: an "Accessed date" is needed only when no publication date is available (i.e., if you have "n.d." as the year of publication). For the in-text citation, use the "n.d." in place of the accessed year.
Author's name or Corporation name. Year of publication. "Title of Webpage." Title of Website. Type Out Website Abbreviations Where Necessary. Accessed month day year [if necessary], http://www.URL.com
(Author date)
Brown, James Robert and Yiftach Fehige. 2023. "Thought Experiments." Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/thought-experiment/
Google. n.d. "Data Practices." Safety Centre. Accessed December 12, 2023. https://safety.google/privacy/data/
(Google, n.d.)
Roberts, Alexander, and James Donaldson, eds. n.d. "ANF01. The Apostolic Fathers with Justin Martyr and Irenaeus: Introductory Note to the Epistle of Mathetes to Diognetus." CCEL, Cristian Classics Ethreal Library. Accessed April 23, 2011. http://www.ccel.org/ccel/schaff/anf01.iii.i.html.
For more details, consult the Chicago Manual of Style, 18th Edition, Section 14.103-14.107, "Websites, Blogs, and Social Media."
The only difference between Notes and Bibliography and Author-Date with regard to bibliography entries is the placement and formatting of the date: Author-Date places the date immediately after the authors' name(s) and does not put brackets around it. Note also that the first author's name in any bibliography entry is inverted (Last name, First name Middle name) and subsequent names are not inverted (First, Middle, then Last name) as shown in the examples below.
Cleese, John, Terry Gilliam, Eric Idle, Terry Jones, and Michael Palin. 2001. "Commentaries." Disc 2. Monty Python and the Holy Grail, special ed. DVD. Directed by Terry Gilliam and Terry Jones. Columbia Tristar Home Entertainment.
Curtis, Michael, and Gregory S. Malin. 1996. "The One with the Princess Leia Fantasy." Friends, season 3, episode 1. Directed by Gail Mancuso. Warner Home Video.
Harwood, John. 2008. "The Pros and Cons of Biden." New York Times video, 2:00. http://www.nytimes.com/video/us/politics/1194817091987/the-pros-and-cons-of-biden.html?module=Search&mabReward=relbias%3Aw.
For more details, consult the Chicago Manual of Style, 18th Edition, Section 14.165-14.167.
The only difference between Notes and Bibliography and Author-Date with regard to bibliography entries is the placement and formatting of the date - Author-Date places the date immediately after the authors' names and does not put brackets around it. Note also that the first author's name in any bibliography entry is inverted (Last name, First name Middle name) and subsequent names are not inverted (First, Middle, then Last name).
Truman, Harry S. 1945. "First Speech to Congress." Transcript and Adobe Flash audio, 18:13. Miller Centre of Public Affairs: University of Virginia. http://millercenter.org/scripps/archive/speeches/detail/3339.
Stan Rogers. 1981. "The Idiot." MP3 audio. Track 6 on Stan Rogers, Northwest Passage. Fogarty's Cove Music.
Note: "MP3 audio" can be replaced with "Spotify," "Apple Music," etc. The rest of the citation remains the same.
Pink Floyd. 1990. Atom Heart Mother. Capitol CDP 7 46381 2, compact disc. Originally released in 1970.
For more details, consult the Chicago Manual of Style, 18th Edition, Section 14.163.
The only difference between Notes and Bibliography and Author-Date with regard to bibliography entries is the placement and formatting of the date - Author-Date places the date immediately after the authors' names and does not put brackets around it. Note also that the first author's name in any bibliography entry is inverted (Last name, First name Middle name) and subsequent names are not inverted (First, Middle, then Last name) as shown in the examples below.
Last name, First name. Year of Publication. "Title of Article." Magazine/Newspaper Name, Month, day of publication. Link (if applicable).
Frank, Michael. 2009. "La Concha Revival: San Juan's Tropical Modernist Gem Makes a Comeback." Architectural Digest. 103-4. August.
Masters, Coco. 2006. "The Takeaway Diet of 2006." Time, December 17.
http://content.time.com/time/magazine/article/0,9171,1570794,00.html.
Borzi, Pat. 2010. "Retirement Discussion Begins Anew for Favre." New York Times, January 25. http://www.nytimes.com/2010/01/26/sports/football/26vikings.html?emc=etal.
For more details, consult the Chicago Manual of Style, 18th Edition, Section 14.87-14.98.
If you are citing an Indigenous Elder or other Indigenous Knowledge Keeper, there are key elements to add to a footnote/endnote and bibliography that acknowledge the authority of Traditional Knowledge and Oral Traditions. These elements include:
Nation or community the Elder or Knowledge Keeper belongs to
Brief description of the information or teaching they have shared
Date the information was shared with you
Treaty territory and city of residence may also be included
Ensure that all of these details are confirmed with the Elder or Knowledge Keeper. Some may prefer to be listed under their Traditional Name rather than their legal name, and sometimes they may prefer to be listed only by their Traditional Name. It is also important to ensure that you have permission to share the information in your essay or publication, and to be aware that additional protocols and permissions may be required if you plan to publish the information.
In-text
(Last Name year)
Reference List
Last Name, First Name (Traditional Name [if applicable]). Year. Nation/community. Treaty territory [if applicable]. Where they live [if applicable]. Topic/subject of communication. Interview, month, day.
***Note: The templates above, provided by CMoS 18, are adapted from the article “More Than Personal Communication: Templates for Citing Indigenous Elders and Knowledge Keepers” by Lorisia MacLeod (doi.org/10.18357/kula.135). You can also watch MacLeod's webinar on YouTube where she discusses these elements in more detail and highlights their importance.
For more on Citing Indigenous Sources, see sections 14.136 & 14.137 in The Chicago Manual of Style, 18th Edition, pages 919-20.
Images should be cited in a caption below the image itself. Label it with Figure # or Fig. # so you can clearly refer back to it in the main text of the paper (e.g. "As shown in Figure 4,...")
Remember to cite the source you are using to view the image. If you saw it in a book, cite the book. If you are looking at the original work, cite the original work.
Fig. 1. Artist first and last name, Title of work. Year of original art, Medium (e.g. Oil on canvas, drawing, sculpture, photograph, etc.), Measurements (e.g. 18.5 x 12 cm). Location of original museum, province, country. Available from: Database name, www.URL.com (accessed month day, year).
Example
Database: Fig. 1. Rogier van der Weyden, Saint Catherine of Alexandria. 1430-1432, Diptych panel, 18.5 x 12 cm. Kunsthistorisches Museum, Vienna, Austria. Available from ARTstor, http://artstor.org (accessed September 30, 2009)
Figure 1. Author first and last name, Title of work. Year of original work, medium, dimensions. From: Author of book, Title of book. City: Publisher, year. Page or plate number.
Example
Fig. 1. Pierre-Auguste Renoir. Young girl and a cow at Saint-Briac. From Judy Le Paul Gaugin and the Impressionists at Pont-Aven. New York: Abbevill Press. 1987. Page 137.
Note: for books, use the year the book was published so the reader can find the source that you used. Do not put the year the original image was created.
Fig. 1. Kostyantyn Steblovskyy. Swanlike End. 2015, Digital Image. Available from: National Geographic. http://photography.nationalgeographic.com/photography/photo-of-the-day/swan-lake-bled/ (Accessed October 14, 2015).
Found a great image on Facebook or Twitter? Trace the image back to its original website and cite it as a web page. Using a profile picture or mobile upload? Make a note in this format:
Creative commons image citations look different because they are copyrighted differently. By indicating the CC info (e.g. CC BY 2.0) the reader is able to know if the image can be shared, modified, and/or sold. For example, CC BY 2.0 means that anyone is able to share and adapt the image for personal or commercial use so long as the original author has been credited and any changes have been noted. The original author is not able to change these rights as long as these rules have been followed.
Template
Title of work by Author or screen name is licensed under CC info
Example
Creative Commons 10th Birthday Celebration San Francisco; by tvol is licensed under CC BY 2.0. https://www.flickr.com/photos/sixteenmilesofstring/8256206923/in/set-72157632200936657
Information regarding Creative Commons citing came from the following source:
"Best practices for attribution”. Creative Commons Wiki. Last modified March 4, 2014. https://wiki.creativecommons.org/wiki/Best_practices_for_attribution
If an image was created by or with the help of artificial intelligence (AI), that fact should be noted (as per Section 3.38 of CMOS 18).
Example
Fig. 4. Image generated by DALL-E 2, April 7, 2023, from the prompt "An ornate bookshelf with a portal into another dimension."
This information comes from page 742 of the Chicago Manual of Style, 18th edition. If you have any further questions, talk to your instructor.
For quotes that span more than one paragraph, format your quotation as follows:
Create a freestanding block, separated from the paragraph with the quote starting on a new line, and indent all lines of the paragraph about 0.5 inches from the left margin. Do not use quotation marks, unless there is a quote within your quote. Unless the paragraph ends following the quote, continue the paragraph with no indentation.
The in-text citation for a block quote in the Author-Date style is placed after the final punctuation of the quote, not before it as with other quoted/paraphrased material. The information in the citation remains the same, as shown in the example below:
Note that, although many Chicago papers use single-spaced block quotations, page 73 (section 2.23) of the Chicago Manual of Style, 18th Edition states that "Prose extracts should have the same line spacing as the surrounding text." Check with your instructor to be sure about spacing requirements on assignments.