Columbia subject headings:
Occupational mobility--Europe--History.
Occupational mobility--United States--History.
Social mobility--Europe--History.
Social mobility--United States--History.
Harvard subject headings:
Occupational mobility--Europe--History.
Occupational mobility--United States--History.
Social mobility--Europe--History.
Social mobility--United States--History.
Princeton subject headings:
Occupational mobility--Europe--History.
Occupational mobility--United States--History.
Social mobility--Europe--History.
Social mobility--United States--History.