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Dyfyniad Arddull ChicagoRay, Anandarup. Cost-benefit Analysis: Issues and Methodologies. Baltimore: Johns Hopkins University Press, 1984.
Dyfyniad MLARay, Anandarup. Cost-benefit Analysis: Issues and Methodologies. Johns Hopkins University Press, 1984.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.