Columbia subject headings:
Harvard subject headings:
Austria--Intellectual life--19th century--Congresses.
Austria--Relations--Spain--Congresses.
Spain--Intellectual life--19th century--Congresses.
Spain--Relations--Austria--Congresses.
Princeton subject headings:
Austria--Foreign relations--1815-1848--Congresses.
Austria--Foreign relations--Spain--Congresses.
Spain--Foreign relations--1814-1886--Congresses.
Spain--Foreign relations--Austria--Congresses.