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Dyfyniad Arddull ChicagoDARA, S.S. A T B OF ENVIRONMENTAL CHEMISRTRY & POLUTION CONTROL. NEW-YORK: MCGRAW HILL, 1987.
Dyfyniad MLADARA, S.S. A T B OF ENVIRONMENTAL CHEMISRTRY & POLUTION CONTROL. MCGRAW HILL, 1987.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.