Columbia subject headings:
Americanization--History--20th century.
Citizenship--Puerto Rico--History--20th century.
Imperialism--History--20th century.
Nationalism--Puerto Rico--History--20th century.
Puerto Rico--Politics and government--20th century.
Harvard subject headings:
Americanization--History--20th century.
Citizenship--Puerto Rico--History--20th century.
Imperialism--History--20th century
Nationalism--Puerto Rico--History--20th century
Puerto Rico--Politics and government--20th century.
Princeton subject headings:
Americanization--History--20th century.
Citizenship--Puerto Rico--History--20th century.
Imperialism--History--20th century.
Nationalism--Puerto Rico--History--20th century.
Puerto Rico--Intellectual life--History--20th century.
Puerto Rico--Politics and government--History--20th century.