Columbia subject headings:
Industries--United States--Classification--Indexes.
Occupations--United States--Classification--Indexes.
United States--Census, 1980.
Harvard subject headings:
Industries--United States--Classification--Indexes.
Occupations--United States--Classification--Indexes.
United States--Census, 1980
United States--Census, 1980.
Princeton subject headings:
Indexes.
Industries--United States--Classification--Indexes.
Occupations--United States--Classification--Indexes.
United States--Census, 20th, 1980.