Dyfyniad APA

(2001). The world book of america's presidents. Chicago: World Book.

Dyfyniad Arddull Chicago

The World Book of America's Presidents. Chicago: World Book, 2001.

Dyfyniad MLA

The World Book of America's Presidents. Chicago: World Book, 2001.

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