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An Introduction to The Bluebook


Rule 4 governs the general use of the short citation forms id., supra, and hereinafter. A number of materials have their own rules governing the use of short citation forms; see the table at the beginning of Rule 4.


Rule 4.1 governs the use of id. generally. 

For law review articles, "use id. when citing the immediately preceding authority within the same footnote or within the immediately preceding footnote when the preceding footnote contains only one authority."

For instance:

Footnote 1: Johnson v. Phelan, 69 F.3d 144, 145 (7th Cir. 1995).

Footnote 2: Id.

(Footnote 1 is the footnote immediately preceding Footnote 2, and cites to only one authority (a case). Footnote 2 also cites to the same case, so id. may be used.)

Footnote 15: Pamela Laufer-Ukeles, Collaborative Family-Making: From Acquisition to Interconnection, 64 VILL. L. REV. 223, 223 (2019). Laufer-Ukeles observes that "domestic adoption involves a widely-accepted system of what is considered 'non-commercial adoption,' even including private adoption...." Id. at 238.

(Here, the same authority is cited twice in a single footnote. Id. is used when citing to the source a second time, after it has already been fully cited.)

If the subsequent citation is to the same material but a different page than was earlier cited, simply list the new page number in the "id." citation:

Footnote 17: Franklin A. Gevurtz, Building a Wall Against Private Actions for Overseas Injuries: The Impact of RJR Nabisco v. European Community, 23 U.C. DAVIS J.INT'L L. & POL'Y 1, 2 (2016).

Footnote 18: Id. at 15.

If the immediately preceding footnote lists more than one authority, id. should not be used in the very next footnote. In this instance, you should use supra. 

For example:

Footnote 20: Hannah L. Buxbaum, The Scope and Limitations of the Presumption Against Extraterritoriality, 110 AJIL UNBOUND 62, 63 (2016); see also Gevurtz, supra note 17, at 3.

Footnote 21: Buxbaum, supra note 20, at 64.


Rule 4.2(a) governs the use of supra.

Supra may be used to refer to a previously fully cited authority, unless id. would be more appropriate or supra cannot be used. 

In the below examples, supra is appropriate because an authority was fully cited in an earlier footnote, but not the immediately preceding one. (In the latter case, id. would be more appropriate.)

Footnote 1: William Baude & Stephen E. Sachs, The Law of Interpretation, 130 HARV. L. REV. 1079, 1107-10 (2017).

Footnote 10: Baude & Sachs, supra note 1, at 1136 ("Interpretive rules can change over time.").

Footnote 5: Green Card Processes and ProceduresU.S. CITIZENSHIP & IMMIGRATION SERVS., []

Footnote 10: U.S. CITIZENSHIP & IMMIGRATION SERVS., supra note 5.

Supra may only be used to refer to certain categories of materials.

Can use for:

Cannot use for:

Legislative hearings

Court filings

Books, pamphlets, reports

Unpublished materials

Nonprint resources

Periodicals and services

Treaties and international agreements

Regulations, directives, and decisions of intergovernmental organizations

Internal cross-references





Legislative materials (other than hearings)


Model Codes


(An exception may be made for any of these authorities if they have extremely long names)


See the relevant rules for appropriate short forms for these materials.


Rule 4.2(b) addresses the use of "hereinafter". Generally, "hereinafter" can be used to shorten names of cited authorities. According to The Bluebook, "after the first citation of the authority, but before any explanatory parenthetical, place the word "hereinafter" and the shortened form in brackets."

The same guidelines as to when "supra" can and cannot be used also apply to "hereinafter". See above under "supra".

Examples for appropriate usage of "hereinafter" (see highlighted areas):

The title of an authority is long or cumbersome, and shortening the title would reduce confusion.

Ex. 1: Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts (Protocol I), June 8, 1977, art. 10 [hereinafter AP I].

Ex. 2: Prosecutor v. Jean-Pierre Bemba Gombo, ICC-01/05-01/08-3636, Judgment on the appeal of Mr. Jean-Pierre Bemba Gombo against Trial Chamber III's “Judgment pursuant to Article 74 of the Statute” (June 8, 2018) [hereinafter Bemba Appeal Judgment].

You need to clearly distinguish between two authorities in one footnote, especially if you plan to cite to one or both of them later on. 

Footnote 3: Lisa Pruitt, Who's Afraid of White Class Migrants? On Denial, Discrediting, and Disdain and Toward a Richer Conception of Diversity), 31 COLUM. J. GENDER & L. 196, 197 (2015) [hereinafter White Class Migrants]; Lisa Pruitt, Welfare Queens and White Trash, 25 S. CAL. INTERDISC. L.J. 289, 290 (2016) [hereinafter Welfare Queens].

Footnote 4: Pruitt, White Class Migrants, supra note 3, at 198.

*Here, both authorities in Footnote 3 are by the same author, Lisa Pruitt. If "hereinafter" was not used to shorten both article titles, Footnote 4 would have looked like this: 

Pruitt, supra note 3, at 198.

In this case, we do not know which Pruitt article from Footnote 3 is being referenced.