Bluebook Citation

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 previously noted, 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.:  This means "for example" and it is used to indicate 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"  and 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.
   

  Signal Groups
  Supportive	Comparative	Contradictory	Background
  No signal E.g. Accord See See Also Cf.	Compare…with…	Contra 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!

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 for the Bluebook guidelines for ordering the authorities.  In general, if one source is considered more authoritative than the others, place that 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 following table:

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