Dyfyniad APA

Bilgere. Imperial. University of Pittsburgh Press.

Dyfyniad Arddull Chicago

Bilgere. Imperial. University of Pittsburgh Press.

Dyfyniad MLA

Bilgere. Imperial. University of Pittsburgh Press.

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