When the President signs a bill into law, he may issue a statement explaining why he is approving the legislation. These statements were traditionally brief and generally did not contain substantive analysis of the legislation. However, in recent administrations they have been used more vigorously and have become a subject of controversy. There is disagreement about their role in and importance to legislative history. See our research guide on Presidential Signing Statements for more sources and information.
The Constitution provides for Congress to appropriate money to be spent by the Federal Government, so when the White House issues the Budget of the United States in February of each year, it can be confusing. For a detailed explanation of the legislature's role in the federal budget process, see the following: CongressLine: The Budget, published on LLRX.com
For a discussion of the role of Congress in the appropriation process, versus the authorization process, see: CongressLine: Authorization and Appropriation, published on LLRX.com
Other types of material that may come out of the legislative process include committee prints and House and Senate documents. Committee prints contain information prepared for the use of the committee and sometimes include special reports or studies or compilations of earlier legislative history documents. House and Senate documents are usually of lesser importance for legislative history and contain special material prepared for Congress.