Cita APA (7th ed.)

Dunlop, F., & Soriano, T. (2013). National Geographic traveler: Portugal (Second edition.). National Geographic Society.

Cita Chicago (17th ed.)

Dunlop, Fiona, i Tino Soriano. National Geographic Traveler: Portugal. Second edition. Washington, D.C: National Geographic Society, 2013.

Cita MLA (9th ed.)

Dunlop, Fiona, i Tino Soriano. National Geographic Traveler: Portugal. Second edition. National Geographic Society, 2013.