Columbia subject headings:
Tramps--United States--History.
Unemployment--United States--History.
United States--Economic conditions.
United States--Social conditions.
Harvard subject headings:
Tramps--United States--History.
Unemployment--United States--History.
United States--Economic conditions.
United States--Social conditions--1865-1918.
United States--Social conditions--1918-1932.
United States--Social conditions--1933-1945.
United States--Social conditions--To 1865.
United States--Social conditions.
Princeton subject headings:
Tramps--United States--History.
Unemployment--United States--History.
United States--Social conditions.