Dyfyniad APA

World health Organization. (2004). Air quality guidelines,Global update 2005: Particulate matter, ozone nitrogen dioxide and sulfur dioxide. World Health Organization.

Dyfyniad Arddull Chicago

World health Organization. Air Quality Guidelines,Global Update 2005: Particulate Matter, Ozone Nitrogen Dioxide and Sulfur Dioxide. copenhagen: World Health Organization, 2004.

Dyfyniad MLA

World health Organization. Air Quality Guidelines,Global Update 2005: Particulate Matter, Ozone Nitrogen Dioxide and Sulfur Dioxide. World Health Organization, 2004.

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