Columbia subject headings:
Political stability--Mexico.
Harvard subject headings:
Mexico--Civilization--20th century--Congresses.
Mexico--History--1910-1946--Congresses.
Mexico--History--1946-1970--Congresses.
Princeton subject headings:
Mexico--Civilization--20th century--Congresses.
Mexico--History--1910-1946--Congresses.
Mexico--History--1948-1970--Congresses.