http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Foreign trade through San Francisco customs district
Board of State Harbor Commissioners for San Francisco Harbor.
Volumes for 1940-1946 compiled from federal customs records by Board of State Harbor Commissioners; for 1947-<1955> from Bureau of the Census records.
Volumes for 1956 published by the San Francisco Port Authority; for 1957- by the Port of San Francisco.
Foreign trade report of San Francisco harbor