(1971). The economics of technological change: Selected readings. Harmondsworth: Penguin.
Dyfyniad Arddull ChicagoThe Economics of Technological Change: Selected Readings. Harmondsworth: Penguin, 1971.
Dyfyniad MLAThe Economics of Technological Change: Selected Readings. Harmondsworth: Penguin, 1971.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.