Each executive department and agency, the Judiciary, Congress, and other major independent establishments are assigned a unique alphabetical identifier, based on the nature of the organization. For example, 'E' is used for the Environmental Protection Agency, 'JU' for Judiciary, and 'NS' for National Science Foundation. One important aspect of the construction of the class number is the use of spacing. A space must be inserted between letters and numbers in the class number unless there is intervening punctuation.
Parentheses are the only exception.
One space must be inserted before and after a parenthesis, unless there is adjacent punctuation. 102d Congress, 2d session.