Dyfyniad APA

(1990). Environmental health criteria 97. World Health Organization.

Dyfyniad Arddull Chicago

Environmental Health Criteria 97. Ginebra: World Health Organization, 1990.

Dyfyniad MLA

Environmental Health Criteria 97. World Health Organization, 1990.

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