Cita APA (7th ed.)
(2001). Portugal, Belgium. OECD Publications Services.
Cita Chicago (17th ed.)
Portugal, Belgium. Paris, France: OECD Publications Services, 2001.
Cita MLA (9th ed.)
Portugal, Belgium. OECD Publications Services, 2001.
Atenció: Aquestes cites poden no estar 100% correctes.