Columbia subject headings:
Harvard subject headings:
Portugal--In literature--Congresses.
Portugal--Relations--Spain--Congresses.
Portuguese literature--History and criticism--Congresses.
Spain--In literature--Congresses.
Spain--Relations--Portugal--Congresses.
Spanish literature--History and criticism--Congresses
Princeton subject headings:
Portugal--In literature--Congresses.
Portugal--Relations--Spain--Congresses.
Portuguese literature--History and criticism--Congresses.
Spain--In literature--Congresses.
Spain--Relations--Portugal--Congresses.
Spanish literature--History and criticism--Congresses.