Bryan, C. (2001). The national geographic society: 100 years of adveenture and discovery. Harry N. Abrams.
Citazione stile Chigago Style (17a edizione)Bryan, C.D.B. The National Geographic Society: 100 Years of Adveenture and Discovery. New York: Harry N. Abrams, 2001.
Citatione MLA (9a ed.)Bryan, C.D.B. The National Geographic Society: 100 Years of Adveenture and Discovery. Harry N. Abrams, 2001.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.