Columbia subject headings:
Government publications--United States--Bibliography.
Maps--Bibliography.
United States--Maps--Bibliography.
United States. Congress--Bibliography.
Harvard subject headings:
Government publications--United States--Bibliography.
Maps--Bibliography
United States--Maps--Bibliography.
United States. Congress--Bibliography.
Princeton subject headings:
Government publications--United States--Bibliography.
Maps--Bibliography.
Maps.
United States--Maps--Bibliography.
United States. Congress--Bibliography.