Columbia subject headings:
Portugal--Bibliography--Periodicals.
Portugal--Imprints--Periodicals.
Portuguese literature--Bibliography--Periodicals.
Harvard subject headings:
Portugal--Bibliography--Periodicals.
Portugal--Imprints--Periodicals.
Portuguese literature--Bibliography--Periodicals.
Princeton subject headings:
Portugal--Bibliography--Periodicals.
Portugal--Imprints--Periodicals.
Portuguese literature--Bibliography--Periodicals.