Columbia subject headings:
Puerto Rico--Politics and government--21st century.
Puerto Rico--Relations--United States.
Self-determination, National--Puerto Rico.
United States--Relations--Puerto Rico.
Harvard subject headings:
Puerto Rico--Politics and government--21st century.
Puerto Rico--Relations--United States.
Self-determination, National--Puerto Rico
United States--Relations--Puerto Rico.
Princeton subject headings:
Puerto Rico--Politics and government--21st century.
Puerto Rico--Relations--United States.
Self-determination, National--Puerto Rico.
United States--Relations--Puerto Rico.