Determinacy of Equilibria in Nonsmooth Economies
Mário Páscoa, Sergio Werlang
Journal of Mathematical Economics, vol. 32, 1999, p. 289-302.

On the Differentiability of the Consumer Demand Function
Paulo Santos Monteiro, Mário Páscoa, Sergio Werlang
Journal of Mathematical Economics, vol. 25, 1996, p. 247-261.