Bluebook Legal Citation

Bluebook Rule (22nd): 18

In general, the Bluebook requires citation to traditional printed sources when available. However, in several instances, the Bluebook permits citation to the digital copy, either directly or as a parallel citation. Notably, the 22nd Edition of the Bluebook added new subsections to Rule 18, including  citation guidance for social media and artificial intelligence. 

General Rules for citing electronic documents

Bluebook Rule (22nd): 18.2.1

Below are some general guidelines for citing electronic media in Bluebook format: 

• You can cite directly to an online source if it is an authenticated, official, or exact copy, and there is no need to append any URL information. 
• The Bluebook encourages citation to "authenticated" web-based sources to ensure the accuracy. Authenticated documents generally have a certificate or logo indicating that a government entity verified the document. If no authenticated source is available, the Bluebook's next preference is an official version of the source, which are as proximate to the original as possible. 
• Exact copies (such as PDFs) are treated similarly to official versions.   
• Append the URL directly to the end of the citation (no connector phrases) for sources that are available in print but are so obscure as to be practically unavailable, and for sources where a parallel citation to the internet source would substantially improve access to the source. 
• Web-based sources that share the characteristics of a print source such that it could be fully cited to under another rule in the Bluebook should include the URL appended directly to the end of the citation. 
• When using an archival tool to save internet sources that change according to algorithmic individuation, like search results, append the archive URL to the full citation in brackets. 

Direct citations to web-based sources 

Note: Pre-22nd Edition of the Bluebook referred to Web-Based Sources as "Internet Sources."

Bluebook Rule (22nd): 18.2.2

• When you cite an internet source, you should include information that will provide the easiest path of access to the reference, like the title, pagination, and publication date.
• If there is an author available, include that information. If there is no clear author, do not use an author unless there is a clear institutional owner of the domain.
• Titles should come either from the title bar or from any heading that identifies the page.
• A website’s main page title should be cited in small caps.
• The date should appear in your citation as it appears on the website. If there is no date, you should include the date that you last visited the cite in a parenthetical after the URL. If the online source has been updated since it was originally posted, use the date and time of the update instead of the original posting date/time.
• If there is a shortlink available that clearly identifies the source site (e.g. wapo.st, imbd.to, etc.), then rule 18.2.2(d) prefers the use of the shortlink. If the shortlink does not clearly identify the source site (e.g. bit.ly), then the full URL should be used.   

Citation to AI-generated content

Bluebook Rule (22nd): 18.3

As of the 22nd Edition, the Bluebook identifies three types of AI-generated content with instructions for citing each: 

• Large language model
• Search results
• AI-generated content 

Generally, the 22nd Edition's rules for citing AI follow these principles: 

• Mandatory PDF versions of screenshots capturing AI outputs
• URLs alone will no longer suffice
• Disclosure of specific search engine and search terms 

Citation to commercial electronic databases

Bluebook Rule (22nd): 18.4

• Cases: You can cite an electronic database when a case is unreported but available on a widely used electronic database. You should include the case name, docket number, database identifier, court name, and full date. Refer to rule 10.8.1(a) for further guidance.

• Statutes: You should cite codes from a commercial electronic database according to rule 12.5(a), adding the name of the electronic database and information about the currency of the database.

• Books, Reports, and Other Nonperiodic Materials: Rule 15.9 specifies that if a source is available in both electronic and print, you can include a citation to a commercial electronic database.
• Periodical Materials: Rule 16.8 provides that when the source is available in two forms, it is permissible to include a direct citation to a commercial electronic database. 

Citation to social media

Bluebook Rule (22nd): 18.10

Earlier editions of the Bluebook (pre-22nd) had minimal examples for citing to social media. Now, the Bluebook explains how to cite visual and audio content, textual content, profiles, and reposts. 

• Citations to visual and audio content include the type of content, the name of the poster and their handle in a parenthetical, the name of the platform, the title or caption of the post, the data and time of post, the URL, and a permanent location where the content will be stored. 
• Citations to textual content are cited similarly to audio/visual, except the type of content is omitted. 
• Social medial profiles are cited in their entirety, similarly to textual content, except the post titles and date are omitted. 
• Reposts are cited like regular posts, except with an appended parenthetic containing the original posters' name and handle.