Electronic Resources (Rule 18)

The Bluebook requires the use and citation of traditional printed sources when available, unless there is a digital copy of the source available that is authenticated, official, or an exact copy of the printed source, as described in rule 18.2.1.

LEXIS, Westlaw, Bloomberg Law, and other commercial electronic databases should be cited in preference to the other sources covered by rule 18. The following rules offer guidance regarding the specific use of commercial electronic databases:


  • Cases, rule 10.8.1
    • For cases that are unreported but available on a widely used electronic database, the case may be cited to that database. 
  • Constitutions, rule 11
    • Indicate parenthetically the name of the publisher, editor, or compiler unless it is an official edition. Indicate the name of the database and information about its currentness as provided by the database itself. 
  • Statutes, rule 12.5
    • Give parenthetically the name of the database and information regarding the currency of the database as provided by the database itself (instead of the code year). 
  • Legislative Materials, rule 13.7
    • Give the name of the database and any identifying codes or numbers that uniquely identify the material. 
  • Regulations, rule 14.4
    • Give the name of the database and any identifying codes or numbers that uniquely identify the material. 
  • Books, Reports, and Other Nonperiodic Materials, rule 15.9
    • Provide a complete citation to the document according to rule 15 as well as a citation to the database. If the database assigns a unique identifier or code to the document, include that identifier or code in your citation. 
    • Do not treat online and print versions of a book interchangeable unless the online source is an exact copy of the original as dictated by rule 18.2.1(a). 
  • Periodical Materials, rule 16.8

Direct Citations to Internet Sources

Cite directly to an internet source when a source does not exist in a traditionally printed form or commercial database. Also, if there the internet has a source exactly the same as the printed version and it would improve access, you may parallel cite to the internet with "available at.

"Model: author; title/statute/case name; pagination (publication date); URL

(1) Typeface the title or party name as you would for a normal citation. Do not underline the URL. If there is no printed comparison, treat the source as unpublished and follow rule 17. See generally rule 18.2.3(b).

(2) If an author is unclear, a title alone may be used [rule 18.2.3(c)].

(3) Only pinpoint cite, if a page number appears in the document itself, e.g. PDFs, and not screen numbers [rule 18.2.3(d)].

(4) Dates. Indicate a year if the date clearly refers to the material cited, else use "last visited X date " in the parenthetical [rule 18.2.3(e)].

          Tom Parfitt, 'Father of the Turkmen' dies aged 66, Guardian Newspaper, December 21, 2006, http://www.theguardian.com/world/2006/dec/21/tomparfitt.

Parallel Citations with Internet Sources - 18.2.2 A parallel internet citation (along with a traditional printed source), is encouraged if the internet source is, 1) identical in content, and 2) will substantially improve access to the source when the printed source is generally unavailable.

After the citation to the traditional source, insert "available at" followed by the internet source (thus indicating that it is merely a secondary location for the material).

For example:

          Town of Concord 2007 Community Preservation Plan, Concord Community Preservation Committee (Sep. 25, 2006), available at http://www.concordnet.org/dplm/CPPlan2006FFINAL.pdf.

Frequently Asked Question: Which URL do I cite? [Rule 18.2.1]

The URL should take the reader directly to the page, with no intervening links in between. If the URL is long and unwieldy, then indicate the root URL with a parenthetical explaining how to access the information. Note, if the explanation itself is long and unwieldy, then resort to inserting the unwieldy URL itself. PDF URLs are preferable over URLs with no PDFs.