Penrose, E. T. (1951). The economics of the international patent system. Johns Hopkins Press.
Dyfyniad Arddull ChicagoPenrose, Edith Tilton. The Economics of the International Patent System. Baltimore: Johns Hopkins Press, 1951.
Dyfyniad MLAPenrose, Edith Tilton. The Economics of the International Patent System. Johns Hopkins Press, 1951.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.