In recognition of the immediate and historical significance of Senate bills, resolutions, hearings, and reports, the secretary oversees the Office of Printing and Document Services, the Office of Senate Security (which maintains classified documents), the United States Senate Library, the Office of Senate Curator, and the Senate Historical Office. The secretary also maintains the Office of Interparliamentary Services to provide support for those interparliamentary conferences in which the Senate participates and to assist senators in international travel. Also under the secretary's direction, the Office of Public Records collects and makes publicly available documents relating to campaign finance, financial ethics, foreign travel, and lobbying.