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Bluebook Citation: Signals

Bluebook Quick Reference

B3 (p. 5):  Bluepages erference for Introductory Signals.

Rule 1.2 (p. 54):  Rule and explanation of Introductory Signals.

Rule 1.3 (p. 56):  Rule for Order of Signals.

Rule 1.4 (p. 56):  Rule for Order of Authorities within a signal.

Signal Use Checklist

Handy reference for using signals:

  • If your authority directly states the proposition or your cite clearly supports the text, you use no signal.
  • If not, refer to Rule 1.2 to select the appropriate signal.
  • Italicize the signal if it is included in the citation sentence.
  • Capitalize the signal if it the first word of the sentence.
  • Include an explanatory parenthetical if the citation requires it.
  • Pay close attention to comma usage, placement, and typeface as dictated in the Bluebook.

The Basics

Citation signals are notoriously confusing.  However, they can be understood and used with a little bit of knowledge.  Signals are used to give the relationship of the source you are citing to your text, and how that relates to other material in the citation sentence.  In simpler terms, it is kind of like a form of code that quickly conveys extra information to the reader.  Signals can be used with any type of authority, and the 11 signals can be organized into four groups based on relationship information:

  1. Those that show support (Supportive)
  2. Those that suggest a useful comparison (Comparative)
  3. Those that indicate contradiction (Contradictory)
  4. Those that indicate background materials (Background)

As noted above, there are 11 signals that you can use.  They are:

  • [no signal]:  Use this when the cite directly supports the text, when the source is a quote, or when you are directly referring to something in your text.  This is used when what you are citing is clearly supporting the text.
  • E.g.:  Meaning "for example", this is used to indicate that the sources you are using are only a small representative of a larger sample.
  • See:  This indicates that the source you are using does not directly state the proposition, but supports it.
  • See also:  This can be used after a no signal cite to a "see" cite to give additional authorities.
  • Accord:  This is used when only one source is mentioned in the text, but additional sources are being cited.
  • Cf.:  Meaning to "compare,"  this is used when an authority doesn't exactly support what you are saying, but still lends support to the argument.
  • Compare...with...:  This contrasts two authorities that have different views on what you are discussing.
  • Contra:  This is used when the authority contradicts the proposition.  
  • But see:  This is used when the authority contradicts the proposition, but without being direct (implicitly).
  • But cf.:  This is used when the authority contrasts the proposition indirectly (by analogy).
  • See generally:  This is used when your cited authority uses background material to support your text





    No signal




    See Also




    But see

    But Cf.

    See Generally


To use a signal:

  • Capitalize your signal only if it begins a sentence.
  • Italicize the signal when it is used in the citation sentence.
  • Make sure to consult Rule 1.2 to ensure the proper use of a signal!

Multiple Signals

If you are using more than one signal, they should be ordered accordingly:

  1. [no signal]
  2. E.g.,
  3. Accord
  4. See
  5. See also
  6. Cf.
  7. Compare...with...
  8. Contra
  9. But see
  10. But cf.
  11. See generally.

In simpler terms, you can remember that signals are generally ordered with supportive first, followed by comparative, then contradictory, then background signals.

Additionally, you may have multiple authorities in a single signal.  This is known as a "string cite."  Refer to Rule 1.4 to see the Bluebook guidelines for ordering the authorities.  In general, if one source is considered more "authoritative" than the others, place this one first in the string cite.  Separate each authority with a semicolon.

Finally, there may be times when you will use a signal that could be aided by the use of a descriptive parenthetical.  There are general rules for when to include a parenthetical with your signal, and these are summarized in the table below:

No Parentheticals

Parentheticals Encouraged

Parentheticals Strongly Recommended

[no signal]

See also



See generally




But cf.







But see



As stated before, include the parenthetical at the end of the citation sentence, after the date.

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