In Bluebook citation, supra vs. infra is a question of direction: supra (Latin for “above”) points the reader back to a source or discussion already cited earlier in the document, while infra (Latin for “below”) points forward to one that appears later. Both are shorthand that lets a brief or law review article avoid repeating full citations, and both are governed by specific Bluebook rules that decide when each is proper.
Supra Points Backward
Supra tells the reader to look back at an earlier part of the document for a full citation or a fuller discussion. If a law review article was cited in full at footnote 5 and needs to appear again at footnote 22, supra handles the second reference without copying the full citation: Copeland, supra note 5, at 3077.
The term only works when the source has already been cited in full somewhere earlier. Without that anchor, a supra reference leads nowhere.
Infra Points Forward
Infra alerts the reader that a source or discussion is coming later in the document. A writer might flag an issue early in a brief and reserve the full analysis for a later section: See infra Part III.B or See cases cited infra note 121.
One boundary matters here. Infra is almost never used as a short-form citation for an authority the way supra is. You would not write “Smith, infra note 45″ to create a short citation. Infra appears when you need to tell the reader that supporting material or a deeper discussion follows in a later section or footnote.1The Bluebook Online. 3.5 Internal Cross-References
Two Settings Where These Words Appear
One source of confusion is that supra and infra show up in two distinct Bluebook contexts, and each follows different rules.
Internal Cross-References Under Rule 3.5
When you point the reader to a different part of your own document, you are making an internal cross-reference. These look like See supra Section IV.A.2 or See infra Part B.2. Both supra and infra are common here because you are simply telling the reader where in your own brief or article to find a related discussion.1The Bluebook Online. 3.5 Internal Cross-References
Footnote-Based Short Citations Under Rule 4.2
Supra also serves as a short-form citation under Rule 4.2, where it replaces a full citation for a secondary source already cited in an earlier footnote. This is the more technically demanding use, with specific formatting requirements and restrictions on which source types qualify.
How to Format a Supra Short Citation
Under Rule 4.2, a supra citation has a specific structure. Start with the author’s last name, add a comma, then the italicized word supra, followed by the word “note” in regular type and the footnote number where the full citation first appeared. If you need to point the reader to a specific page, add a comma and “at” followed by the page number.
A properly formatted example looks like this: Baude & Sachs, supra note 1, at 1136. Only the word supra is italicized. The author name, the word “note,” and the footnote number all stay in regular type.2The Bluebook. 4.2 Supra and Hereinafter
When a document cites multiple works by the same author, the footnote number does the work of distinguishing them. If you cited Professor Smith’s 2019 article in footnote 8 and her 2022 book in footnote 15, writing Smith, supra note 8, at 340 tells the reader exactly which work you mean.
Supra vs. Id.
Id. and supra both point backward, but they are not interchangeable. Id. (short for idem, meaning “the same”) refers only to the immediately preceding citation. If footnote 11 cites a single source and footnote 12 cites the same source, footnote 12 should use id., not supra. Whenever id. works, it takes priority.
Supra steps in when id. cannot do the job. That happens in two common situations: when one or more different sources have been cited between the original citation and the current one, or when the immediately preceding footnote cited multiple authorities, making id. ambiguous. If the reader cannot tell which source id. would refer to, switch to a supra citation with the author name and footnote number.
Where Supra Is Not Allowed
Not every source type qualifies for a supra citation. The Bluebook prohibits supra and hereinafter for the following categories:
- Cases. Use the short-form case name instead.
- Statutes. Use the abbreviated statutory citation.
- Constitutions. Always cite in their standard short form.
- Legislative materials such as debates, though hearings are an exception.
- Restatements and model codes, which follow their own citation conventions.
- Regulations. Cite using the regulatory short form.
Each of these source types has its own dedicated short-form rule. There is a narrow exception: when an authority’s name is extremely long, the Bluebook permits supra or hereinafter even for otherwise prohibited source types. This comes up rarely, and overusing it invites scrutiny.2The Bluebook. 4.2 Supra and Hereinafter
Where Supra Is Allowed
Supra is designed for secondary and miscellaneous sources that lack their own dedicated short-form rules. The permitted categories include:
- Books and pamphlets
- Periodicals, including law review articles and journals
- Legislative hearings
- Reports
- Court filings
- Unpublished materials
- Nonprint resources
- Services
- Treaties and international agreements
A simple rule of thumb: if the source has its own Bluebook short-form rule, use that rule. If it does not, supra is likely the right tool.
Setting Up a Short Name With Hereinafter
Hereinafter is a companion tool that establishes a nickname for a source with an unwieldy title. It appears in brackets at the end of the first full citation: [hereinafter Short Name]. After that, subsequent supra citations use the short name in place of the author’s last name.
Two formatting details trip people up. First, “hereinafter” is not italicized, even though supra is. Second, it must appear inside brackets, not parentheses. The correct form is [hereinafter Short Name], not (hereinafter Short Name).2The Bluebook. 4.2 Supra and Hereinafter Government reports with lengthy institutional authors are a classic candidate for a hereinafter short name.
Mistakes That Give You Away
A handful of errors show up repeatedly in law school papers and even in court filings.
Using supra for a case is the most frequent mistake. Cases always use their own short form, no matter how many times they have already been cited. Writing Miranda, supra note 3 is wrong; write Miranda v. Arizona, 384 U.S. at 444 instead.
Using supra when id. is available is another common slip. If the immediately preceding footnote cites only one source and you are citing the same source, id. is required.
Forgetting the footnote number defeats the purpose of the citation. Writing Smith, supra without “note 12” forces the reader to hunt through every prior footnote. Always include the specific footnote number where the full citation appears.
Confusing supra with infra happens less often but is more embarrassing, because it sends the reader searching in the wrong direction. A quick mental check works: if you are pointing backward, use supra; if you are pointing forward, use infra.