Columbia subject headings:
Caribbean Area--Foreign relations--United States.
Caribbean Area--Relations--Puerto Rico.
Puerto Rico--Relations--Caribbean Area.
United States--Foreign relations--Caribbean Area.
Harvard subject headings:
Caribbean Area--Foreign relations--United States.
Caribbean Area--Relations--Puerto Rico.
Puerto Rico--Relations--Caribbean Area.
United States--Foreign relations--Caribbean Area.
Princeton subject headings:
Caribbean Area--Foreign relations--Puerto Rico--1945-.
Puerto Rico--Foreign relations--Caribbean Area.