Dyfyniad APA

(2005). National Geographic visual history of the world. National Geographic Society.

Dyfyniad Arddull Chicago

National Geographic Visual History of the World. Washington, D.C: National Geographic Society, 2005.

Dyfyniad MLA

National Geographic Visual History of the World. National Geographic Society, 2005.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.