Columbia subject headings:
Constitutional law--Puerto Rico.
Economic history--Puerto Rico.
Puerto Rico--Economic conditions--1918-1952.
Puerto Rico--Politics and government--1952-1998.
Harvard subject headings:
Puerto Rico--Economic conditions--1918-
Puerto Rico--Politics and government--1952-
Princeton subject headings:
Puerto Rico--Economic conditions--1918-.
Puerto Rico--Politics and government--1952-1998.