Partial Holder continuity for discontinuous elliptic problems with VMO-coefficients

We establish partial Holder continuity for vector-valued solutions u : Omega -> R-N to elliptic systems of the type div a(x, u, Du) = 0 in Omega, as well as for minimizers u : Omega -> R-N of quasi-convex functionals F[u] := integral(Omega) f(x, u, Du) dx, where the structure function a, respectively, the integrand f is possibly discontinuous with respect to x. More precisely, we merely impose a uniform VMO-condition with respect to the x-dependence and continuity with respect to the u-dependence and prove Holder continuity of the solutions, respectively, the minimizers outside of a negligible set.