Columbia subject headings:
Mexico--Politics and government--1970-1988.
Opposition (Political science)--Mexico--History--20th century.
Partido Revolucionario Institucional.
Political parties--Mexico--History--20th century.
Harvard subject headings:
Mexico--Politics and government--1970-1988.
Opposition (Political science)--Mexico--History--20th century.
Partido Revolucionario Institucional.
Political parties--Mexico--History--20th century
Princeton subject headings:
Mexico--Politics and government--1970-.
Opposition (Political science)--Mexico--History--20th century.
Partido Revolucionario Institucional.
Political parties--Mexico--History--20th century.