United States. Congress. Senate. Committee on Environment and Public Works.
United States. Congress. House. Committee on Public Works and Transportation. Subcommittee on Surface Transportation.
United States. General Accounting Office
Woodward-Clyde Consultants
United States. Congress. Senate. Committee on Commerce, Science, and Transportation. Subcommittee on Surface Transportation.
United States. Congress. House. Committee on Interior and Insular Affairs.