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Citing Sources

Referencing, avoiding plagiarism, and presentation of the Chicago Style

Audiovisual and Electronic Sources

Electronic content is often volatile and manipulable. If a source changes or becomes unavailable, citations to that source may need to be adjusted. It is therefore important to check the accuracy of citations to electronic content as close to the date of publication as possible.

Some databases or electronic journals provide persistent links to facilitate citations. The Digital Object Identifier (DOI) allows a unique and persistent identifier to be assigned to electronic sources. It is possible to find an electronic document through its DOI on this website.

A DOI can also be converted into a URL in this way: (example: j.jet.2003.12.008 ). This link will take you directly to the document.  

This website allows you to automatically format a citation in the style of your choice starting from the DOI.

The "author-date" system may be less suitable for electronic and audiovisual sources, because it relies on the date of publication and it is sometimes difficult to find the date of publication of an electronic document. For this reason, examples are sometimes given only for the  "notes and bibliography" system.

First Name Last Name, Title of the movie. Original release date; place of publication: Publisher, date of publication. Type of medium.

Florian Henckel von Donnersmarck, dir. The Lives of Others. 2006; Santa Monica, CA: Lions Gate Entertainment, 2007. DVD.

Last Name, First Name. Title. Original release date; place of publication: Publisher, date of publication. Type of medium.

Henckel von Donnersmarck, Florian, dir. The Lives of Others. 2006; Santa Monica, CA: Lions Gate Entertainment, 2007. DVD.

Scenes are individually accessible on DVDs, so they can be treated as chapters and cited by title or by number.

Example (note)
"Dans la forteresse", La grande illusion, directed by Jean Renoir (1937; Boulogne-Billancourt: Studio Canal, 2001), DVD.

It is also possible to cite supplementary material, such as critical commentaries or documents included in the DVD’s supplements. If the material is original to a particular edition of the DVD, it is not necessary to mention the original release date of the film. 

"Making Of", The Lives of Others, DVD. Directed by Florian Henckel von Donnersmarck. Santa Monica, CA: Lions Gate Entertainment, 2007.

Information on the Internet is often published without a clear indication of authorship, title, publisher or date, i.e. without standard facts of publication. If no or very few facts of publication can be determined, it is still necessary  to include information beyond the URL, which may change or become obsolete. A complete citation must indicate not only where a source is or was located, but also what a source is. For original content from online sources other than journals, include as much of the following as can be determined: title of the site, owner or sponsor of the site, title of the page, date of publication or date of revision or change, URL. It is advisable to keep a copy of any source that is likely to change or disappear.

"Title of the page or the document," Title of Web site, Owner/Sponsor of Web site, Date of publication or revision or access date, URL.

"Bibliographies with BibTex," Andrew Roberts (website),

Author of the post, "Title of the post", Title of the blog, Date of the post, URL.

Catriona Murdoch and Wayne Jordash, "Will Seven Millions Starving Yemenis Ever Find Justice?", iLawyer (blog), October 2, 2017,

If a date cannot be determined from the source, include the date the material was last accessed. If the material is a recording of a speech or other performance, or if it is a digital version of a published source, include information about the original performance or source. For multimedia designed to run in a web browser, it is not necessary to indicate a file format; if a downloadable file was consulted, indicate the format.

YouTube Video

"Gianfranco Rosi on Fire at Sea", Toronto International Film Festival (TIFF) Originals, October 18, 2016, video, 3:51,

TED Talk

Thunberg, Greta. "The disarming case to act right now on climate change." Filmed November 2018 in Stockholm, Sweden. TED video, 11:05.


"Building militaries in fragile states", interview of Mara Karlin by Jack Miraldi, February 21, 2019, in The Modern War Institute Podcast, podcast, 23:09,

Access dates in online source citations are of limited value because earlier versions are often unavailable to readers, and the author may have consulted several versions in the course of research. The Chicago Manual of Style recommends therefore including the date of last access only in time-sensitive fields such as law, where even small corrections can be significant, or if the professor or the editor requests it.  Include a date of access if the date of publication or last modification cannot be determined.

A very long URL can often be shortened simply by finding a better version of the link. However, shortened versions provided by "URL shorteners", designed primarily for use with social media, should never be used, as such services may disappear, and the original URL identifies the domain name and other elements that may be important for citation.