Using Full Duality to Show that Simultaneously Additive Direct and Indirect Utilities Implies Unitary Price Elasticity of Demand
Paul A. Samuelson, Using Full Duality to Show that Simultaneously Additive Direct and Indirect Utilities Implies Unitary Price Elasticity of Demand, Econometrica, Vol. 33, No. 4 (Oct., 1965), pp. 781-796