Dyfyniad APA

American Geographical Society's Focus on Geography. Wiley-Blackwell.

Dyfyniad Arddull Chicago

American Geographical Society's Focus on Geography. Wiley-Blackwell.

Dyfyniad MLA

American Geographical Society's Focus on Geography. Wiley-Blackwell.

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