APA (7th ed.) Zitazioa
Organisation for Economic Co-operation and Development. (1981). Portugal: 1981. OECD Publishing.
Chicago Style (17th ed.) Zitazioa
Organisation for Economic Co-operation and Development. Portugal: 1981. Paris: OECD Publishing, 1981.
MLA (9th ed.) Zitazioa
Organisation for Economic Co-operation and Development. Portugal: 1981. OECD Publishing, 1981.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.