Columbia subject headings:
Harvard subject headings:
Mexico, North--Civilization--Congresses.
Mexico, North--Economic conditions--Congresses.
Mexico, North--Social conditions--Congresses.
Mexico, Southeast--Civilization--Congresses.
Mexico, Southeast--Economic conditions--Congresses.
Mexico, Southeast--Social conditions--Congresses.
Mexico--Boundaries--Congresses.
Princeton subject headings:
Mexico, North--Civilization--Congresses.
Mexico, North--Economic conditions--Congresses.
Mexico, North--Social conditions--Congresses.
Mexico, Southeast--Civilization--Congresses.
Mexico, Southeast--Economic conditions--Congresses.
Mexico, Southeast--Social conditions--Congresses.
Mexico--Boundaries--Congresses.