Higher regularity of solutions to the singular $p$-Laplacean system
  This paper has been withdrawn by the authors due to a mistake in the proof of the chief result. In particular Theorem 1.3 is correct, while Theorem 1.1 and Theorem 1.2 hold with \mu>0 and a suitable restriction on the exponent p. The proof of the modified statements is slightly different. 
Francesca Crispo and Paolo Maremonti
math.AP