Columbia subject headings:
African Americans--Puerto Rico--History--20th century.
Nationalism--Puerto Rico--History--20th century.
Puerto Rico--Civilization--20th century.
Puerto Rico--History--20th century.
Puerto Rico--Race relations--History--20th century.
United States--Economic conditions--20th century.
United States--Politics and government--20th century.
Harvard subject headings:
African Americans--Puerto Rico--History--20th century.
Nationalism--Puerto Rico--History--20th century
Puerto Rico--20th century--Pictorial works.
Puerto Rico--History--20th century.
Puerto Rico--Race relations--History--20th century.
United States--Economic conditions--20th century.
United States--Politics and government--20th century.
Princeton subject headings:
African Americans--Puerto Rico--History--20th century.
Nationalism--Puerto Rico--History--20th century.
Puerto Rico--20th century--Pictorial works.
Puerto Rico--History--20th century.
Puerto Rico--Race relations--History--20th century.
United States--Economic conditions--20th century.
United States--Politics and government--20th century.