Columbia subject headings:
Puerto Rico--Civilization.
Puerto Rico--History.
Puerto Rico--Relations--Spain.
Puerto Rico--Relations--United States.
Spain--Relations--Puerto Rico.
United States--Relations--Puerto Rico.
Harvard subject headings:
Princeton subject headings:
Puerto Rico--Civilization.
Puerto Rico--History.
Puerto Rico--Relations--Spain.
Puerto Rico--Relations--United States.
Spain--Relations--Puerto Rico.
United States--Relations--Puerto Rico.