Multiplicity of Nodal Solutions for a Critical Quasilinear Equation with Symmetry

We consider the quasilinear problem $\mbox{div}(|\nabla u|^{p-2}\nabla u) + \lambda|u|^{q-2}u + |u|^{p^*-2}u=0$ in $\Omega$, $u=0$ on $\partial \Omega$, where $\Omega \subset \real^N$ is a bounded smooth domain, $N \geq p^2$, $\lambda>0$ and $p