  We consider Kirchhoff equations for vibrating bodies in any dimension in
presence of a time-periodic external forcing with period 2pi/omega and
amplitude epsilon, both for Dirichlet and for space-periodic boundary
conditions.
  We prove existence, regularity and local uniqueness of time-periodic
solutions of period 2pi/omega and order epsilon, by means of a Nash-Moser
iteration scheme. The results hold for parameters (omega, epsilon) in Cantor
sets having measure asymptotically full as epsilon tends to 0.
  (What's new in version 2: the case of finite-order Sobolev regularity, the
case of space-periodic boundary conditions, a different iteration scheme in the
proof, some references).
