APA (7th ed.) Zitazioa
(2001). Portugal, Belgium. OECD Publications Services.
Chicago Style (17th ed.) Zitazioa
Portugal, Belgium. Paris, France: OECD Publications Services, 2001.
MLA (9th ed.) Zitazioa
Portugal, Belgium. OECD Publications Services, 2001.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.