Dyfyniad APA

World health organization. (1961). Air pollution. World Health Organization.

Dyfyniad Arddull Chicago

World health organization. Air Pollution. Geneva: World Health Organization, 1961.

Dyfyniad MLA

World health organization. Air Pollution. World Health Organization, 1961.

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