Columbia subject headings:
Elections--Mexico.
Mexico--Politics and government--1946-1970.
Partido Comunista Mexicano.
Harvard subject headings:
Elections--Mexico
Mexico--Politics and government--1946-1970
Mexico--Politics and government--1970-1988.
Partido Comunista Mexicano.
Princeton subject headings:
Elections--Mexico.
Mexico--Politics and government--1946- .
Partido Comunista Mexicano.