Columbia subject headings:
Agricultural laborers--California--Economic conditions.
Agricultural laborers--California--Social conditions.
Depressions--1929--United States.
Migration, Internal--California--History--20th century.
Migration, Internal--Oklahoma--History--20th century.
Harvard subject headings:
Agricultural laborers--California--Economic conditions.
Agricultural laborers--California--Social conditions.
California--Population--History--20th century.
Depressions--1929--United States
Depressions--1929--United States--History.
Dust Bowl Era, 1931-1939.
Migration, Internal--California--History--20th century.
Migration, Internal--Oklahoma--History--20th century.
Migration, Internal--United States--History--20th century
Oklahoma--Population--History--20th century.
Princeton subject headings:
Agricultural laborers--California--Economic conditions.
Agricultural laborers--California--Social conditions.
Depressions--1929--United States--History.
Migration, Internal--California--History--20th century.
Migration, Internal--Oklahoma--History--20th century.