A. P. Migliorini:
Everywhere regularity for a class of elliptic systems with $p$, $q$ growth conditions
Rend. Ist. Mat. Trieste Vol. XXXI, p. 203-234, 1999

E. Mascolo, A. P. Migliorini:
Everywhere regularity for vectorial functionals with general growth      
ESAIM, Control Optim. Calc. Var.  Vol. 9, p. 399-418, 2003

G. Cupini, A. P. Migliorini:
Hölder continuity for local minimizers of a nonconvex variational problem
J. Convex Anal. Vol. 10, N. 2, p. 389-408, 2003