Dyfyniad APA

(1991). The Facts on File encyclopedia of the 20th century. New York: Facts on File.

Dyfyniad Arddull Chicago

The Facts On File Encyclopedia of the 20th Century. New York: Facts on File, 1991.

Dyfyniad MLA

The Facts On File Encyclopedia of the 20th Century. New York: Facts on File, 1991.

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