APA (7th ed.) Zitazioa
Organisation for Economic Co-operation and Development. (1999). Bulgaria: 1998-1999. OECD Publishing.
Chicago Style (17th ed.) Zitazioa
Organisation for Economic Co-operation and Development. Bulgaria: 1998-1999. Paris: OECD Publishing, 1999.
MLA (9th ed.) Zitazioa
Organisation for Economic Co-operation and Development. Bulgaria: 1998-1999. OECD Publishing, 1999.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.