Dyfyniad APA

World Health Organization. (2011). Guidelines for drinking-water quality (4th.). World Health Organization.

Dyfyniad Arddull Chicago

World Health Organization. Guidelines for Drinking-water Quality. 4th. Geneva, Switzerland: World Health Organization, 2011.

Dyfyniad MLA

World Health Organization. Guidelines for Drinking-water Quality. 4th. World Health Organization, 2011.

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