Dyfyniad APA

(1990). Diseases of the digestive system. World health organization.

Dyfyniad Arddull Chicago

Diseases of the Digestive System. Ginebra: World health organization, 1990.

Dyfyniad MLA

Diseases of the Digestive System. World health organization, 1990.

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