Layard, R. (1972). Cost-benefit analysis. Penguin Education.
Dyfyniad Arddull ChicagoLayard, Richard. Cost-benefit Analysis. London: Penguin Education, 1972.
Dyfyniad MLALayard, Richard. Cost-benefit Analysis. Penguin Education, 1972.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.