Columbia subject headings:
Labor--Mexico.
Mexico--Economic conditions--1918-
Mexico--Foreign relations--United States.
Mexico--Politics and government--1910-1946.
United States--Foreign relations--Mexico.
Working class--Mexico.
Harvard subject headings:
Labor and laboring classes--Mexico.
Labor--Mexico.
Mexico--Economic conditions--1918-
Mexico--Foreign relations--United States.
Mexico--Politics and government--1910-1946.
United States--Foreign relations--Mexico.
Working class--Mexico
Princeton subject headings: