Columbia subject headings:
Mexico--Politics and government--1946-1970.
Harvard subject headings:
Mexico--Politics and government--1910-1946.
Mexico--Politics and government--1946-1970
Mexico--Politics and government--1970-1988.
Partido Revolucionario Institucional.
Princeton subject headings:
Mexico--Politics and government--1910-1946.
Mexico--Politics and government--1946-1970.
Mexico--Politics and government--1970-.
Partido Revolucionario Institucional.