(1990). Environmental health criteria 96. World Health Organization.
Dyfyniad Arddull ChicagoEnvironmental Health Criteria 96. Ginebra: World Health Organization, 1990.
Dyfyniad MLAEnvironmental Health Criteria 96. World Health Organization, 1990.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.