Utbud och efterfrågan: Ricardos åsikt

"You say demand and supply regulate value - this, I think, is saying nothing."

David Ricardo i brev till Thomas Malthus, oktober 1820. Works of David Ricardo, red Piero Sraffa, vol 8 s 279, Cambridge UP 1952. Cit i Roland Meek, "Value in the History of Economic Thought", i Smith, Marx and After, Chapman & Hall 1977.