2 U.S.C. § 145
Copies of journals and documents
Two copies of the journals and documents, and of each book printed by either House of Congress, well bound in calf, shall be deposited in the Library, and must not be taken therefrom.
Two copies of the journals and documents, and of each book printed by either House of Congress, well bound in calf, shall be deposited in the Library, and must not be taken therefrom.