Columbia subject headings:
African Americans--Employment--Sources.
African Americans--Migrations--History--20th century--Sources.
Migration, Internal--United States--History--20th century--Sources.
Harvard subject headings:
African Americans--Migrations--History--20th century--Sources.
African Americans--Migrations--History--20th century.
Migration, Internal--United States--History--20th century
Migration, Internal--United States--History--20th century--Sources.
Princeton subject headings:
African Americans--History--1877-1964.
African Americans--Migrations--History--20th century.
African Americans--Social conditions--20th century--Sources.
African Americans--Southern States--History--20th century.
Protest movements--United States--History--20th century--Sources.
Rural-urban migration--United States--History--20th century--Sources.
United States--Race relations--Sources.