By looking at the different versions of a bill as it made its way through Congress, you may be able to infer what the legislature had in mind with respect to a particular provision. Federal bill numbers are preceded by an "S." (for Senate) or "H.R." (for House of Representatives). During each congressional term (which consists of two 1 year sessions), the first bill introduced in the Senate and the House of Representatives becomes S. 1 and H.R. 1 respectively, and each subsequent bill during that term is numbered sequentially (i.e., S. 2, H.R. 2, S. 3, H.R. 3, etc.). Thus, in order to locate a particular bill, you need to know not only the bill number but also the congressional term in which the bill was introduced. Each 2-year congressional term is designated as a separate Congress, with its own number (e.g., 104th Congress, 105th Congress, etc.). The first year of a given Congress is the first session; the second year is the second session.
After a federal bill is introduced in the House or the Senate, it is referred to a Congressional committee. If and when a bill is sent back to the whole house for consideration, it is usually accompanied by a committee report. The committee report typically provides a summary and analysis of the bill's content and a statement regarding the bill's intent.
After a bill is passed by one house of Congress, it must be sent to the other house for approval. If the House and Senate do not pass the exact same version of a bill, a conference committee is convened to settle disagreements between the two houses and iron out a final version of the bill. The conference committee usually issues its own report, which is typically the most important report for purposes of determining legislative intent.
Senate and House report numbers are preceded by "S. Rep." (for Senate Report) or "H. Rep." (for House Report). The first part of each report number designates the particular Congress in which the report was issued and the second part designates the specific report issued in that particular house during that Congress (e.g., S. Rep. 104-22 refers to the 22nd report issued in the Senate during the 104th Congress).
Most federal bills are discussed in hearings before Congressional committees. Transcripts of congressional hearings are sometimes published and are usually considered part of a bill's legislative history. A published hearing contains all witness testimony before the committee (including prepared statements as well as the question and answer portion of the hearing). In some cases, exhibits are also included. As a source of legislative intent, transcripts of hearings are not as authoritative as reports. Comments made at hearings may represent only the views of individual legislators, individual witnesses, or special interest groups, and the comments may be contradictory.
Debates on the floor of the House and Senate sometimes shed light on legislative intent, but as with hearings, remarks made during debates may represent only the views of individual legislators and may be contradictory. Also, members of Congress may alter or supplement their remarks prior to their publication.
Transcripts of Congressional floor debates are published in the Congressional Record. The numbers in a Congressional Record citation refer to the volume and page in the set where the remarks can be found (e.g., 75 Cong. Rec. 11235 refers to volume 75, page 11,235 of the Congressional Record).
The President may issue a statement when signing or vetoing a bill passed by Congress. This statement may include an interpretation of an ambiguous provision. Presidential statements are contained in the (Daily or Weekly) Compilation of Presidential Documents as well as in the Public Papers of the President.