Columbia subject headings:
Industries--United States.
United States--Economic conditions--1918-1945.
United States--Social conditions.
Working class--United States.
Harvard subject headings:
Princeton subject headings:
Europe--Economic conditions--1918-1945.
Europe--Social conditions--20th century.
Industries--Europe.
Industries--United States.
United States--Economic conditions--1918-1945.
United States--Social conditions--1918-1932.
Working class--Europe.
Working class--United States.