Dyfyniad APA

National Geographic Society (U.S.). (1991). National Geographic picture atlas of our world. The National Geographic Society.

Dyfyniad Arddull Chicago

National Geographic Society (U.S.). National Geographic Picture Atlas of Our World. Washington D.C: The National Geographic Society, 1991.

Dyfyniad MLA

National Geographic Society (U.S.). National Geographic Picture Atlas of Our World. The National Geographic Society, 1991.

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