Columbia subject headings:
Harvard subject headings:
Argentina--Foreign relations.
Brazil--Foreign relations.
Geopolitics--South America.
Paraguay--Foreign relations.
Rio de la Plata Region (Argentina and Uruguay)--History.
Uruguay--Foreign relations.
Princeton subject headings:
Argentina--Foreign relations.
Brazil--Foreign relations.
Geopolitics--South America.
Paraguay--Foreign relations.
Río de la Plata Region (Argentina and Uruguay)--History.
Uruguay--Foreign relations.