The Bluebook

United States Constitution:

U.S. Const. art 2, § 2, cl. 3. 

U.S. Const. amend. I.

Short forms other than id. may not be used. 

For more information see Rule 11. 

Federal Statutes

Federal Statutes citations should include the official name of the act and the published source in which the act can be found. A parenthetical may be included to show the year the source was published or the year the statute was passed. 

Age Discrimination in Employment Act of 1967, Pub. L. No 90-202, 81 Stat. 602 (1967).

When citing to he United States Code, the official code for federal statutes is the United States Code (USC). Unofficial codes are also available. 

Citations to the United States Code include:

1. Title Number 
2. Abbreviated Name of the code
3. the section numbers in which the code is codified 
4. the year of the cited code edition (this may be omitted when citing the official code) 

The same statute listed above would be cited in the code as

29 U.S.C. § 621.

For more information see Rule 12

State Statutes

States vary on how to cite to the code.Table 1.3 lists the official and unofficial statutory compilations for each state, in order of Bluebook preference. 

The general layout of a state code citation is:

1. Abbreviated name of the code
2. The section number of what you are citing
3. The year of the code volume (not the year it was enacted

For example, Florida can be found on page 252. 

The preference order of the compilations are: Florida Statutes, West's Florida Statutes Annotated, and then LexisNexis Florida Statutes Annotated. 

Florida Statutes should be cited as Fla. Stat. § x (year).