Columbia subject headings:
Mexico--Foreign relations--1946-1970--Congresses.
Mexico--Politics and government--1946-1970--Congresses.
Mexico--Politics and government--1970-1988--Congresses.
Harvard subject headings:
Mexico--Foreign relations--1970-1988.
Princeton subject headings:
Mexico--Foreign relations--1946-1970--Congresses.
Mexico--Foreign relations--1970-1988--Congresses.
Mexico--Politics and government--1946-1970--Congresses.
Mexico--Politics and government--1970---Congresses.