Columbia subject headings:
Harvard subject headings:
Puerto Rico--History--1898-1952
Puerto Rico--History--1952-
Puerto Rico--Politics and government--1898-1952.
Puerto Rico--Politics and government--1952-
Princeton subject headings:
Puerto Rico--History--1952-1998--Miscellanea.
Puerto Rico--Relations--United States--Miscellanea.
Trivia and miscellanea.
United States--Relations--Puerto Rico--Miscellanea.